Photosensitive composition and pattern forming method using the same

ABSTRACT

A photosensitive composition containing a compound capable of generating a specific acid having the plural number of sulfonic groups by irradiation with an actinic ray or a radiation and a pattern forming method using the same.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a photosensitive composition whichcauses reaction by irradiation with an actinic ray or a radiation,whereby its property changes. In more detail, the invention relates to aresist composition to be used in the manufacturing step ofsemiconductors such as IC, the manufacture of circuit boards such asliquid crystals and thermal heads, and other fabrication steps.

2. Description of the Related Art

A chemically amplified resist composition is a pattern forming materialof forming an acid in an exposed area by irradiation with the radiationsuch as far ultraviolet light and changing the solubility in a developerbetween the actinic ray-irradiated area and the non-irradiated area dueto a reaction using the formed acid as a catalyst, to form a pattern ona substrate.

In the case where a KrF excimer laser is an exposure light source, sincea resin comprising as a basic skeleton poly (hydroxystyrene) exhibitinglow absorption mainly in a region of 248 nm is used as the majorcomponent, this chemically amplified system is able to form a goodpattern at high sensitivity and high resolution and is a good system ascompared with a conventional naphthoquinonediazide/novolak resin system.

On the other hand, in the case where a light source having a shorterwavelength, for example, an ArF excimer laser (193 nm), is used as anexposure light source, since an aromatic group-containing compoundexhibits high absorption substantially in a region of 193 nm, even theforegoing chemically amplified system was not satisfactory yet.

For this reason, a resist for ArF excimer laser containing a resinhaving an alicyclic hydrocarbon structure has been developed.

With respect to an acid generating agent which is the majorconstitutional component of a chemically amplified resist, a variety ofcompounds have been found. JP-A-9-309874 describes a positivephotosensitive composition containing a divalent arylsulfonic acidsulfonium salt or iodonium salt.

However, performances such as an exposure margin in which theperformance changes due to a fine change of the exposure amount anddensity dependency in which the performance changes due to the patterndensity such as a dense pattern and an isolated pattern are notsatisfactory yet, and therefore, improvements have been demanded.

Also, in a resin having an alicyclic hydrocarbon structure, the systembecomes extremely hydrophobic as an evil influence of the alicyclichydrocarbon structure. Therefore, development with a tetramethylammoniumhydroxide (herein-after referred to as “TMAH”) aqueous solution that hashitherto been widely used as a resist developer becomes difficult. Also,there is observed a phenomenon in which a resist peels away from asubstrate during the development.

For example, JP-A-9-73173 and JP-A-10-161313 describe resist materialsusing an acid sensitive compound containing an alkali-soluble groupprotected by an alicyclic group-containing structure and a structuralunit such that the alkali-soluble group is eliminated by an acid,thereby making the compound alkali-soluble. These materials are of anexcellent design from which a hydrophilic/hydrophobic contrast isobtained because the structure containing a hydrophobic alicyclic groupis eliminated. However, these materials were not satisfactory yet withrespect to the developability with a TMAH aqueous solution and peelingof a resist from a substrate during the development. For this reason,there have been various investigations with respect to the introductionof a hydrophilic group into a resin having an alicyclic hydrocarbon siteintroduced thereinto.

Japanese Patent No. 2,776,273 and JP-A-11-109632 describe the use of aresin containing a polar group-containing alicyclic functional group andan acid decomposable group in a radiation sensitive material.

Also, JP-A-9-90637, JP-A-10-207069, JP-A-10-274852, JP-A-2001-188351,and Japanese Patent No. 3,042,618 describe photoresist compositionscontaining a polymer obtained by copolymerizing a (meth)acrylatederivative having a lactone structure with other polymerizable compound.

Also, JP-A-2001-109154, JP-A-2000-137327, JP-A-2002-296783, andJP-A-2001-215704 describe positive working photoresist compositionscontaining a copolymer resin of the foregoing lactone monomer and amonomer having a hydroxyadamantane structure as a polar group-containingalicyclic functional group.

As described previously, though there have been investigated a varietyof measures for improving the hydrophobicity of the resin, the foregoingtechniques involve a lot of unsatisfactory points, and improvements aredesired. In particular, in forming a fine pattern with a line width ofnot more than 100 nm, it is required that a resist composition does notdepend upon the coverage of a mask (rate of an exposed area to anunexposed area) or the pitch of a pattern, i.e., the presence of patterndensity, and is hardly influenced by a change of the pattern formingcondition (exposure amount and focus) (that is, the process window iswide). However, in the foregoing compositions, there was still room forimprovements regarding the process window.

Also, in the resist for ArF excimer laser containing a resin having analicyclic hydrocarbon structure, there was encountered such a problemthat in forming a fine pattern with a line width of not more than 100nm, the resist pattern collapses so that the subsequent processing of asubstrate by dry etching cannot be achieved. This problem becomesremarkable as the processed line width becomes fine. Thus, a resistcapable of forming a fine pattern without causing collapse is demanded.

Also, under the circumstance where it is necessary to form a finepattern with a line width of not more than 100 nm, in particular, informing an isolated pattern, it becomes difficult to ensure the focuslatitude, i.e., the depth of focus (DOF). Thus, a resist compositionhaving a wider DOF performance is demanded.

In forming a resist pattern from a resist composition, the compositionis in general used upon dissolution in a proper solvent. In this regard,the precision, resolution, etc. of the resulting resist pattern are alsolargely influenced by the kind or combination of the solvent to be usedin forming a resist pattern. Moreover, when the composition in thesolution state is coated (especially, rotary coated) on a substrate,there was a problem that the surface of the coated resist film is notalways satisfactorily uniform so that the uniformity in film thicknessis not satisfactory.

Hitherto, for the solution of a chemical amplification type radiationsensitive composition, various solvents such as ethers, glycol ethers,glycol ether acetates, cellosolve esters, aromatic hydrocarbons,ketones, and esters have been used, and their kinds include manydifferent materials. Also, the characteristics of the resist pattern areclosely related to the composition to be used.

For example, JP-A-10-254139 describes a radiation sensitive resincomposition comprising (A) an alkali-insoluble or sparinglyalkali-soluble acid-cleavable group-containing resin having an alicyclicskeleton in the principal chain and/or the side chain, the resinbecoming alkali-soluble upon cleavage of the acid-cleavable group, (B) aradiation sensitive acid generating agent capable of generating an acidby irradiation with the radiation, and (C) a solvent comprising amixture of a cyclic ketone or at least one kind selected from the groupconsisting of propylene glycol monoalkyl ether acetates and alkyl2-hydroxypropionates and a linear ketone, the radiation sensitive resincomposition being excellent with respect to transparency against theradiation, dry etching resistance, uniformity in film thickness,adhesion to a substrate, sensitivity, resolution, developability, andthe like.

Also, JP-A-2000-241964 describes that a photoresist compositioncontaining a ketone based solvent such as cyclohexanone, isobutyl methylketone, 2-heptanone, 3-heptanone, 4-heptanone, cyclopentanone,2-methylcyclopentanone, 3-methylcyclopentanone, 2-methylcyclohexanone,3-methylcyclohexanone, and 2,4-dimethylpentanone exhibits shear thinningproperty and that even in an atmosphere where an amine in a highconcentration is present, an excellent photoresist fine pattern can beobtained without adding another step for the removal of the amine,whereby a reduction of the costs can be achieved.

However, the application range of the contents disclosed in thesedocuments is not always wide, and it is the actual situation that it isquite difficult to find out an adequate solvent or combinations thereofcorresponding to the composition containing a resin, a photo acidgenerating agent, additives, and the like from the viewpoint of theoverall performance as a resist. Further, in forming a fine pattern witha line width of not more than 100 nm, improvements in the defocuslatitude performances regarding the prevention from pattern collapse andisolated line pattern of the resist were still demanded.

SUMMARY OF THE INVENTION

Accordingly, an object of the invention is to provide an excellentphotosensitive composition having a wide exposure margin and littledensity dependency.

Further, another object of the invention is to provide a positiveworking resist composition that is low in the generation of patterncollapse in the formation of a fine pattern of not more than 110 nm andwide in the defocus latitude (DOF) in the formation of an isolated linepattern, or a positive working resist composition capable of ensuring awide process window in the formation of isolated line and densepatterns, and a pattern forming method using the same.

The invention has the following constructions, and the foregoing objectsof the invention are achieved by these constructions.

(1) A photosensitive composition comprising (A) a compound thatgenerates a sulfonic acid by irradiation with one of an actinic ray anda radiation, wherein the sulfonic acid is represented by general formula(I):A₁

A₂—SO₃H)_(n)  (I)

in which A₁ represents a connecting group having a valence of n;

each of A₂'s represents a single bond or a divalent aliphatic group, andA₂'s are the same or different, with proviso that at least one of agroup represented by A₁ and groups represented by A₂'s has afluorine-atom; and

n represents an integer of from 2 to 4.

(2) A positive photosensitive composition which is a photosensitivecomposition according to (1), further comprising (B) a resin thatincreases an solubility of the resin (B) in an alkaline developer by anaction of an acid.

(3) The positive photosensitive composition as described in (2) above,

wherein the resin (B) has a fluorine atom.

(4) The positive photosensitive composition as described in (3) above,

wherein the resin (B) has a hexafluoroisopropanol structure.

(5) The positive photosensitive composition as described in (2) above,

wherein the resin (B) has a hydroxystyrene structural unit.

(6) The positive photosensitive composition as described in (2) above,

wherein the resin (B) is (Ba) a resin having a monocyclic or polycyclicalicyclic hydrocarbon structure.

(7) The positive photosensitive composition as described in (6) above,

wherein the resin (B) further has a repeating unit having a lactonestructure.

(8) The positive photosensitive composition as described in (6) above,which further comprises:

(Ha) a solvent comprising at least one cyclic ketone.

(9) The positive photosensitive composition as described in (2) above,

wherein the resin (B) has at least one repeating unit selected from arepeating unit represented by general formula (1), a repeating unitrepresented by general formula (2), and a repeating unit represented bygeneral formula (3), wherein the resin (Baa) increases a solubility ofthe resin (Baa) in an alkaline developer by an action of an acid:

in which R represents a hydrogen atom or a methyl group;

A represents a single bond or a connecting group; and

ALG represents a group represented by any one of general formulae (pI)to (pV):

in which R₁₁ represents a methyl group, an ethyl group, an n-propylgroup, an isopropyl group, an n-butyl group, an isobutyl group, or asec-butyl group;

Z represents an atomic group necessary for forming an alicyclichydrocarbon group together with a carbon atom;

R₁₂ to R₁₆ each independently represents a linear or branched alkylgroup having from 1 to 4 carbon atoms or an alicyclic hydrocarbon group,with proviso that at least one of R₁₂ to R₁₄ and any one of R₁₅ and R₁₆represents an alicyclic hydrocarbon group;

R₁₇ to R₂₁ each independently represents a hydrogen atom, a linear orbranched alkyl group having from 1 to 4 carbon atoms or an alicyclichydrocarbon group, with proviso that at least one of R₁₇ to R₂₁represents an alicyclic hydrocarbon group and any one of R₁₉ and R₂₁represents a linear or branched alkyl group having from 1 to 4 carbonatoms or an alicyclic hydrocarbon group; and

R₂₂ to R₂₅ each independently represents a hydrogen atom, a linear orbranched alkyl group having from 1 to 4 carbon atoms or an alicyclichydrocarbon group, with proviso that at least one of R₂₂ to R₂₅represents an alicyclic hydrocarbon group and R₂₃ and R₂₄ may be takentogether to form a ring,

in which R_(1a) represents a hydrogen atom or a methyl group;

W₁ represents a single bond, or a single group or a combination of twoor more groups selected from the group consisting of an alkylene group,an ether group, a thioether group, a carbonyl group, and an ester group;and

Lc represents a lactone residue represented by any one of generalformulae (IV), (V-1) to (V-6) and (VI):

in which R_(a1), R_(b1), R_(c1), R_(d1), and R_(e1) each independentlyrepresents a hydrogen atom or an alkyl group having from 1 to 4 carbonatoms; and

m and n each independently represents an integer of from 0 to 3, and(m+n) is from 2 to 6,

in which R_(1b) to R_(5b) each independently represents a hydrogen atom,an alkyl group, a cycloalkyl group, an alkenyl group, or COOR_(6b),wherein R_(6b) represents an alkyl group, and two of R_(1b) to R_(5b)may be taken together to form a ring, and

in which R₃₀ represents a hydrogen atom or a methyl group; and

R₃₁ to R₃₃ each independently represents a hydrogen atom, a hydroxylgroup or an alkyl group, with proviso that at least one of R₃₁ to R₃₃represents a hydroxyl group.

(10) The positive photosensitive composition as described in (9) above,

wherein the resin (B) has a repeating unit represented by the generalformula (1) and at least one repeating unit selected from a repeatingunit represented by the general formula (2) and a repeating unitrepresented by the general formula (3).

(11) The positive photosensitive composition as described in (9) above,

wherein the resin (B) has a repeating unit represented by the generalformula (1), a repeating unit represented by the general formula (2),and a repeating unit represented by the general formula (3).

(12) The positive photosensitive composition as described in any one of(2) to (11) above, which further comprises (C) a dissolution inhibitingcompound that decomposes by an action of an acid and increases asolubility of the compound (C) in an alkaline developer, the compound(C) having a molecular weight of not more than 3,000.

(13) A positive photosensitive composition which is a photosensitivecomposition according to (1), further comprising:

(D) a resin soluble in an alkaline developer; and

(C) a dissolution inhibiting compound that decomposes by an action of anacid and increases a solubility of the compound (C) in an alkalinedeveloper, the compound (C) having a molecular weight of not more than3,000.

(14) A negative photosensitive composition which is a photosensitivecomposition according to (1), further comprising:

(D) a resin soluble in an alkaline developer; and

(E) an acid crosslinking agent that cross-links with the resin (D) by anaction of an acid.

(15) The photosensitive composition as described in any one of (1) to(14) above,

wherein in the general formula (I), A₂ represents an aliphatic grouphaving a structure represented by general formula (II):

in which Rf₁ and Rf₂ each independently represents a hydrogen atom, ahalogen atom, an alkyl group or a cycloalkyl group, with proviso that atleast one of Rf₁ and Rf₂ represents a fluorine atom or a fluoroalkylgroup.

(16) The photosensitive composition as described in any one of (1) to(15) above,

wherein the compound (A) is one kind selected from a sulfonium saltcompound of the sulfonic acid represented by the general formula (I), aniodonium salt compound of the sulfonic acid represented by the generalformula (I), and an ester compound of the sulfonic acid represented bythe general formula (I).

(17) The photosensitive composition as described in any one of (1) to(16) above,

wherein each of —SO₃H's in the sulfonic acid represented by the generalformula (I) directly connects a carbon atom to which at least one of afluorine atom and a fluoroalkyl group is directly connected.

(18) The photosensitive composition as described in any one of (1) to(17) above,

which further comprises (A′) a compound having one sulfonic acid group,the compound (A′) generating a sulfonic acid by irradiation with one ofan actinic ray and a radiation.

(19) The photosensitive composition as described in (18) above,

wherein the compound (A′) is a monovalent perfluoroalkanesulfonic acidsulfonium salt.

(20) The photosensitive composition as described in any one of (1) to(19) above,

which further comprises a mixed solvent of a solvent containing ahydroxyl group in its structure and a solvent not containing a hydroxylgroup in its structure.

(21) The photosensitive composition as described in any one of (1) to(20) above, which further comprises at least one of (F) a basic compoundand (G) at least one of a surfactant containing a fluorine atom, asurfactant containing a silicon atom and a surfactant containing afluorine atom and a silicon atom.

(22) The photosensitive composition as described in (21) above,

wherein the basic compound (F) is at least one of (i) a compound havinga structure selected from an imidazole structure, a diazabicyclostructure, an onium hydroxide structure, an onium carboxylate structure,a trialkylamine structure, an aniline structure, and a pyridinestructure, (ii) an alkylamine derivative having at least one of ahydroxyl group and an ether bond and (iii) an aniline derivative havingat least one of a hydroxyl group and an ether bond.

(23) A pattern forming method comprising:

forming a film by using a photosensitive composition as described in anyone of (1) to (22) above;

exposing the film, so as to form a exposed film; and

developing the exposed film.

DETAILED DESCRIPTION OF THE INVENTION

The invention will be described below in detail.

Incidentally, in the expressions of groups (atomic groups) in thepresent specification, the expression which does not express the term“substituted” or “unsubstituted” includes not only one having nosubstituent but also one having a substituent. For example, the term“alkyl group” includes not only an alkyl group having no substituent(unsubstituted alkyl group) but also an alkyl group having a substituent(substituted alkyl group).

The positive photosensitive composition of the invention, morepreferably the positive working resist composition, contains (A) acompound capable of generating an acid by irradiation with the actinicray or the radiation and (B) a resin which is decomposed by the actionof an acid, whereby its solubility in an alkaline developer increases,and if desired, further contains (C) a dissolution inhibiting compoundwhich is decomposed by the action of an acid, whereby its solubility inan alkaline developer increases, and which has a molecular weight of notmore than 3,000, or contains (A) a compound capable of generating anacid by irradiation with the actinic ray or the radiation, (D) a resinsoluble in an alkaline developer, and (C) a dissolution inhibitingcompound which is decomposed by the action of an acid, whereby itssolubility in an alkaline developer increases, and which has a molecularweight of not more than 3,000.

The negative photosensitive composition of the invention, morepreferably the negative working resist composition, contains (A) acompound capable of generating an acid by irradiation with the actinicray or the radiation, (D) a resin soluble in an alkaline developer, and(E) an acid crosslinking agent capable of crosslinking with the resinsoluble in an alkaline developer by the action of an acid.

[1] Compound capable of generating a sulfonic acid represented by thegeneral formula (I) by irradiation with the actinic ray or the radiation(sometimes referred to as “compound (A)”):A₁

A₂—SO₃H)_(n)  (I)

In the general formula (I),

A₁ represents a connecting group having a valence of n,

each of A₂'s represents a single bond or a divalent aliphatic group, andA₂'s are the same or different, with proviso that at least one of thegroup represented by A₁ and the group represented by A₂'s has a fluorineatom, and

n represents an integer of from 2 to 4.

Examples of the connecting group as A₁ include an alkylene group, acycloalkylene group, an arylene group, an alkenylene group, a singlebond, an ether bond, an ester bond, an amide bond, a sulfide bond, aurea bond, a carbonyl group, a carbon atom, and a connecting group ofthe plural number of these groups.

The alkylene group as A₁ may have a substituent and preferably has from1 to 8 carbon atoms. Examples thereof include a methylene group, anethylene group, a propylene group, a butylene group, a hexylene group,and an octylene group.

The cycloalkylene group as A₁ may have a substituent and preferably hasfrom 3 to 8 carbon atoms. Examples thereof include a cyclopentylenegroup and a cyclohexylene group.

The alkenylene group as A₁ may have a substituent and preferably hasfrom 2 to 6 carbon atoms. Examples thereof include an ethenylene group,a propenylene group, and a butenylene group.

The arylene group as A₁ may have a substituent and preferably has from 6to 15 carbon atoms. Examples thereof include a phenylene group, atolylene group, and a naphthylene group.

Examples of substituents which may be substituted on these groupsinclude ones having active hydrogen such as a cycloalkyl group, an arylgroup, an amino group, an amide group, a ureido group, a urethane group,a hydroxyl group, and a carboxyl group, a halogen atom (for example, afluorine atom, a chlorine atom, a bromine atom, and an iodine atom), analkoxy group (for example, a methoxy group, an ethoxy group, a propoxygroup, and a butoxy group), a thioether group, an acyl group (forexample, an acetyl group, a propanoyl group, and a benzoyl group), anacyloxy group (for example, an acetoxy group, a propanoyloxy group, anda benzoyloxy group), an alkoxyarbonyl group (for example, amethoxycarbonyl group, an ethoxycarbonyl group, and a propoxycarbonylgroup), a cyano group, and a nitro group. Also, with respect to thearylene group, an alkyl group (for example, a methyl group, an ethylgroup, a propyl group, and a butyl group) can be further enumerated.

The divalent aliphatic group as A₂ is preferably an alkylene group or acycloalkylene group each having from 1 to 8 carbon atoms, and morepreferably an alkylene group or a cycloalkylene group each substitutedwith a fluorine atom or a fluoroalkyl group.

The alkylene group as A₂ may have a substituent and preferably has from1 to 8 carbon atoms. Examples thereof include a methylene group, anethylene group, a propylene group, a butylene group, a hexylene group,and an octylene group.

The cycloalkylene group as A₂ may have a substituent and preferably hasfrom 3 to 8 carbon atoms. Examples thereof include a cyclopentylenegroup and a cyclohexylene group.

The fluoroalkyl group (alkyl group in which at least one hydrogen atomis substituted with a fluorine atom) which the alkylene group orcycloalkylene group as A₂ preferably has may have a substituent andpreferably has from 1 to 8 carbon atoms, and more preferably from 1 to 3carbon atoms. Examples thereof include a monofluoromethyl group, adifluoromethyl group, a trifluoromethyl group, a 2,2,2-trifluoroethylgroup, a pentafluoroethyl group, a 2,2,3,3,3-pentafluoropropyl group, aheptafluoropropyl group, a 2,2,3,3,4,4,4-heptafluorobutyl group, anonafluorobutyl group, and a perfluorohexyl group. Examples of theadditional substituent of the fluoroalkyl group include a hydroxylgroup, an alkoxy group (preferably one having from 1 to 5 carbon atoms),a halogen atom, and a cyano group.

Also, it is preferable that A₂ is an aliphatic group having a structureof the following formula (II).

In the general formula (II), Rf₁ and Rf₂ each independently represents ahydrogen atom, a halogen atom, an alkyl group, or a cycloalkyl group,with proviso that at least one of Rf₁ and Rf₂ represents a fluorine atomor a fluoroalkyl group.

The alkyl group as Rf₁ and Rf₂ may have a substituent and preferably hasfrom 1 to 8 carbon atoms. Specific examples thereof include a methylgroup, an ethyl group, a propyl group, an n-butyl group, and a sec-butylgroup. As the substituent which the alkyl group as Rf₁ and Rf₂ may have,a halogen atom can be preferably enumerated.

The cycloalkyl group as Rf₁ and Rf₂ may have a substituent andpreferably has from 3 to 8 carbon atoms. Examples thereof include acyclopentyl group and a cyclohexyl group.

The fluoroalkyl group as Rf₁ and Rf₂ is a group resulting fromsubstitution of a fluorine atom on the foregoing alkyl group orcycloalkyl group. Examples thereof include the foregoing groupsenumerated for the fluoroalkyl group.

In the general formula (I), n represents an integer of from 2 to 4,preferably 2 or 3, and further preferably 2.

Incidentally, it is preferable that the structure of the general formula(II) is bonded to the adjacent position of the sulfonic acid (the sulfuratom of the sulfonic acid atomic group).

Further, as the sulfonic acid represented by the general formula (I), asulfonic acid represented by the following general formula (III) is morepreferable.A₁

(CF₂)_(b)—A₃—(CF₂)_(a)—SO₃H)_(n)  (III)

A₁ and n are synonymous with A₁ and n in the general formula (I).

A₃ represents a single bond, an ether bond, a sulfide bond, an alkylenegroup, a cycloalkylene group, or an arylene group, and more preferably asingle bond or an ether bond. A₃ of the number of n may be the same ordifferent.

a represents an integer of from 1 to 4.

b represents an inter of from 0 to 4.

The alkylene group, the cycloalkylene group and the arylene group as A₃are the same as the alkylene group, the cycloalkylene group and thearylene group as A₁, respectively.

a preferably represents 1 or 2.

b preferably represents from 0 to 2.

As the sulfonic acid represented by the general formula (I), sulfonicacids represented by the following general formulae (Ia) to (Ih) arefurther preferable.

A₄ represents an alkylene group, a cycloalkylene group, an arylenegroup, or a group in which the plural number of these groups areconnected to each other via at least one of a single bond, an etherbond, an ester bond, an amide bond, a sulfide bond, and a urea bond.

n1 to n5 each represents an integer of from 1 to 8, and preferably aninteger of from 1 to 4.

Rf₃ each independently represents a fluorine atom or a fluoroalkylgroup.

The alkylene group, the cycloalkylene group and the arylene group as A₄are the same as the alkylene group, the cycloalkylene group and thearylene group as A₁, respectively.

The fluoroalkyl group as Rf₃ is the same as that described above.

Preferred specific examples of the sulfonic acid represented by thegeneral formula (I) will be given below.

As the compound (A) capable of generating a sulfonic acid represented bythe general formula (I) by irradiation with the actinic ray or theradiation, one kind selected from sulfonium salt compounds or iodoniumsalt compounds of the sulfonic acid represented by the general formula(I) or one kind selected from ester compounds of the sulfonic acidrepresented by the general formula (I) is preferable, and compoundsrepresented by the following general formulae (A-1) to (A-5) are morepreferable.

In the foregoing general formula (A-1), R₂₀₁, R₂₀₂, and R₂₀₃ eachindependently represents an organic group.

A₁ and A₂ are synonymous with A₁and A₂ in the general formula (I),respectively.

n represents an integer of from 2 to 4.

The organic group as R₂₀₁, R₂₀₂, and R₂₀₃ generally has from 1 to 30carbon atoms, and preferably from 1 to 20 carbon atoms.

Also, two of R₂₀₁ to R₂₀₃ may be taken together to form a ringstructure, and the ring may contain an oxygen atom, a sulfur atom, anester bond, an amide bond, or a carbonyl group.

Examples of the group which two of R₂₀₁ to R₂₀₃ are taken together toform include an alkylene group (for example, a butylene group and apentylene group).

As specific examples of the organic group as R₂₀₁, R₂₀₂, and R₂₀₃,corresponding groups in compounds (A-1a) to (A-1c) described later canbe enumerated.

Incidentally, compounds having the plural number of the structuresrepresented by the general formula (A-1) may be employed. For example,compounds having a structure in which at least one of R₂₀₁ to R₂₀₃ of acompound represented by the general formula (A-1) is bonded to at leastone of R₂₀₁ to R₂₀₃ of another compound represented by the generalformula (A-1) may be employed.

More preferably, the compounds (A-1a), (A-1b) and (A-1c) described belowcan be enumerated as the compound (A-1).

The compound (A-1a) is an aryl sulfonium compound in which at least oneof R₂₀₁ to R₂₀₃ of the foregoing general formula (A-1) is an aryl group,that is, a compound in which an aryl sulfonium is a cation.

In the aryl sulfonium compound, all of R₂₀₁ to R₂₀₃ may be an arylgroup, or a part of R₂₀₁ to R₂₀₃ may be an aryl group, with theremainder being an alkyl group or a cycloalkyl group.

Examples of the aryl sulfonium compound include triaryl sulfoniumcompounds, diarylalkyl sulfonium compounds, aryldialkyl sulfoniumcompounds, diarylcycloalkyl sulfonium compounds, and aryldicycloalkylsulfonium compounds.

As the aryl group of the aryl sulfonium compound, a phenyl group and anaphthyl group are preferable, and a phenyl group is more preferable. Inthe case where the aryl sulfonium compound has two or more aryl groups,the two or more aryl groups may be the same or different.

The alkyl group or cycloalkyl group which the aryl sulfonium compoundhas as the need arises is preferably a linear or branched alkyl grouphaving from 1 to 15 carbon atoms or a cycloalkyl group having from 3 to15 carbon atoms. Examples thereof include a methyl group, an ethylgroup, a propyl group, an n-butyl group, a sec-butyl group, a t-butylgroup, a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.

The aryl group, alkyl group and cycloalkyl group as R₂₀₁ to R₂₀₃ mayeach have an alkyl group (for example, one having from 1 to 15 carbonatoms), a cycloalkyl group (for example, one having from 3 to 15 carbonatoms), an aryl group (for example, one having from 6 to 14 carbonatoms), an alkoxy group (for example, one having from 1 to 15 carbonatoms), a halogen atom, a hydroxyl group, or a phenylthio group as asubstituent. As the substituent, a linear or branched alkyl group havingfrom 1 to 12 carbon atoms, a cycloalkyl group having from 3 to 12 carbonatoms, and a linear, branched or cyclic alkoxy group having from 1 to 12carbon atoms are preferable; and an alkyl group having from 1 to 4carbon atoms and an alkoxy group having from 1 to 4 carbon atoms aremore preferable. The substituent may be substituted on any one of threeR₂₀₁ to R₂₀₃ or may be substituted on all of three R₂₀₁ to R₂₀₃. Also,in the case where R₂₀₁ to R₂₀₃ are an aryl group, it is preferable thatthe substituent is substituted at the p-position of the aryl group.

Next, the compound (A-1b) will be described below.

The compound (A-1b) is a compound in the case where in the formula(A-1), R₂₀₁ to R₂₀₃ each independently represents an aromatic ring-freeorganic group. The aromatic ring as referred to herein includes aromaticrings containing a hetero atom.

The aromatic ring-free organic group as R₂₀₁ to R₂₀₃ generally has from1 to 30 carbon atoms, and preferably from 1 to 20 carbon atoms.

R₂₀₁ to R₂₀₃ are each independently preferably an alkyl group or acycloalkyl group (especially, a linear, branched or cyclic oxoalkylgroup which may have a double bond in the chain and analkoxycarbonylmethyl group are preferable), an allyl group, or a vinylgroup; more preferably a linear, branched or cyclic 2-oxoalkyl group;and most preferably a linear or branched 2-oxoalkyl group.

The alkyl group as R₂₀₁ to R₂₀₃ is preferably a linear or branched alkylgroup having from 1 to 20 carbon atoms (for example, a methyl group, anethyl group, a propyl group, a butyl group, and a pentyl group).

The cycloalkyl group as R₂₀₁ to R₂₀₃ is preferably a cyclic alkyl grouphaving from 3 to 10 carbon atoms (for example, a cyclopentyl group, acyclohexyl group, and a norbornyl group)

The 2-oxoalkyl group as R₂₀₁ to R₂₀₃ may be linear, branched or cyclicand is preferably a group having >C═O at the 2-position of the foregoingalkyl group or cycloalkyl group.

The alkoxy group in the alkxoycarbonylmethyl group as R₂₀₁ to R₂₀₃ ispreferably an alkoxy group having from 1 to 5 carbon atoms (for example,a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and apentyloxy group).

Each of R₂₀₁ to R₂₀₃ may be further substituted with a halogen atom, analkoxy group (for example, one having from 1 to 5 carbon atoms), ahydroxyl group, a cyano group, or a nitro group.

The compound (A-1c) is a compound represented by the following generalformula (A-1c) and is a compound having an arylacyl sulfonium saltstructure.

In the general formula (A-1c), R₂₁, represents an aryl group, andpreferably a phenyl group or a naphthyl group. Examples of a preferredsubstituent which the aryl group as R₂₁₁ may have include an alkylgroup, a cycloalkyl group, an alkoxy group, an acyl group, a nitrogroup, a hydroxyl group, an alkoxycarbonyl group, and a carboxy group.

R₂₁₂ and R₂₁₃ each independently represents a hydrogen atom, an alkylgroup, or a cycloalkyl group.

Y₂₀₁ and Y₂₀₂ each independently represents an alkyl group (especially,a 2-oxoalkyl group, an alkoxycarbonylalkyl group, and a carboxyalkylgroup are preferable), a cycloalkyl group (especially, a 2-oxocycloalkylgroup, an alkoxycarbonylcycloalkyl group, and a carboxycycloalkyl groupare preferable), an aryl group, or a vinyl group.

R₂₁₁ and R₂₁₂ may be taken together to form a ring structure; R₂₁₂ andR₂₁₃ may be taken together to form a ring structure; and Y₂₀₁ and Y₂₀₂may be taken together to form a ring structure. These ring structuresmay contain an oxygen atom, a sulfur atom, an ester bond, or an amidebond. Examples of the group which R₂₁, and R₂₁₂ are taken together toform, the group which R₂₁₂ and R₂₁₃ are taken together to form, and thegroup which Y₂₀₁ and Y₂₀₂ are taken together to form include a butylenegroup and a pentylene group.

A₁ and A₂ are synonymous with A₁ and A₂ in the general formula (I),respectively.

n represents an integer of from 2 to 4.

The alkyl group as R₂₁₂ and R₂₁₃ is preferably an alkyl group havingfrom 1 to 20 carbon atoms.

The cycloalkyl group as R₂₁₂ and R₂₁₃ is preferably a cycloalkyl grouphaving from 3 to 20 carbon atoms.

The alkyl group as Y₂₀₁ and Y₂₀₂ is preferably an alkyl group havingfrom 1 to 20 carbon atoms.

The cycloalkyl group as Y₂₀₁ and Y₂₀₂ is preferably a cycloalkyl grouphaving from 3 to 20 carbon atoms.

The 2-oxoalkyl group as Y₂₀₁ and Y₂₀₂ is preferably a group having >C═Oat the 2-position of the alkyl group as Y₂₀₁ and Y₂₀₂.

The 2-oxocycloalkyl group as Y₂₀₁ and Y₂₀₂ is preferably a grouphaving >C═O at the 2-position of the cycloalkyl group as Y₂₀₁ and Y₂₀₂.

The alkoxycarbonyl group in the alkoxycarbonylalkyl group andalkxoycarbonylcycloalkyl group as Y₂₀₁ and Y₂₀₂ is preferably analkoxycarbonyl group having from 2 to 20 carbon atoms.

Y₂₀₁ and Y₂₀₂ are each preferably an alkyl group or a cycloalkyl groupeach having 4 carbon atoms or more, preferably from 4 to 16 carbonatoms, and further preferably from 4 to 12 carbon atoms.

Also, it is preferable that at least one of R₂₁₂ and R₂₁₃ is an alkylgroup or a cycloalkyl group; and it is more preferable that both R₂₁₂and R₂₁₃ are an alkyl group or a cycloalkyl group.

In the general formula (A-2), R₂₀₄ and R₂₀₅ each independentlyrepresents an aryl group, an alkyl group, or a cycloalkyl group.

A₁ and A₂ are synonymous with A₁ and A₂ in the general formula (I),respectively.

n represents an integer of from 2 to 4.

The aryl group as R₂₀₄ and R₂₀₅ is preferably a phenyl group or anaphthyl group, and more preferably a phenyl group.

The alkyl group as R₂₀₄ and R₂₀₅ is preferably a linear or branchedalkyl group having from 1 to 10 carbon atoms (for example, a methylgroup, an ethyl group, a propyl group, a butyl group, and a pentylgroup).

The cycloalkyl group as R₂₀₄ and R₂₀₅ is preferably a cycloalkyl grouphaving from 3 to 10 carbon atoms (for example, a cyclopentyl group, acyclohexyl group, and a norbornyl group).

Examples of the substituent which the group as R₂₀₄ and R₂₀₅ may haveinclude an alkyl group (for example, one having from 1 to 15 carbonatoms), a cycloalkyl group (for example, one having from 3 to 15 carbonatoms), an aryl group (for example, one having from 6 to 15 carbonatoms), an alkoxy group (for example, one having from 1 to 15 carbonatoms), a halogen atom, a hydroxyl group, and a phenylthio group.

In the general formula (A-3), A represents an alkylene group, analkenylene group, or an arylene group.

A₁ and A₂ are synonymous with A₁ and A₂ in the general formula (I),respectively.

n represents an integer of from 2 to 4.

In the general formula (A-4), R₂₀₆ represents an alkyl group, acycloalkyl group, or an aryl group.

R₂₀₇ represents an alkyl group (especially, an oxoalkyl group ispreferable), a cycloalkyl group (especially, an oxocycloalkyl group ispreferable), a cyano group, or an alkoxycarbonyl group, and preferably ahalogen-substituted alkyl group, a halogen-substituted cycloalkyl group,or a cyano group.

A₁ and A₂ are synonymous with A₁ and A₂ in the general formula (I),respectively.

n represents an integer of from 2 to 4.

In the general formula (A-5), R₂₀₈ and R₂₀₉ each represents a hydrogenatom, an alkyl group, a cycloalkyl group, a cyano group, a nitro group,or an alkoxycarbonyl group, and preferably a halogen-substituted alkylgroup, a halogen-substituted cycloalkyl group, a nitro group, or a cyanogroup.

R₂₁₀ represents a hydrogen atom, an alkyl group, a cycloalkyl group, acyano group, or an alkoxycarbonyl group.

A₁ and A₂ are synonymous with A₁ and A₂ in the general formula (I),respectively.

Of these, the compounds represented by the general formula (A-1) areespecially preferable.

Specific examples of the compound (A) will be given below, but it shouldnot be construed that the invention is limited thereto.

The compound (A) can be synthesized by synthesizing a derivative of thesulfonic acid represented by the general formula (I) and then subjectingit to salt exchange with an onium halide, etc. or esterification with ahydroxyl group-containing compound. The derivative of the sulfonic acidrepresented by the general formula (I) can be synthesized by methodsdescribed in, for example, JP-A-2001-322975, J. Org. Chem., Vol. 56, No.22 (1991), p. 6348, and Synthesis, (1989), p. 464.

The content of the compound (A) in the photosensitive composition of theinvention is preferably from 0.1 to 20% by weight, more preferably from0.5 to 10% by weight, and further preferably from 1 to 7% by weightbased on the solids of the composition.

(Associative Acid Generating Agent)

In the invention, a compound capable of generating an acid byirradiation with the actinic ray or the radiation may be further usedjointly in addition to the compound (A).

The amount of the photo acid generating agent which can be used jointlyis usually from 100/0 to 20/80, preferably from 100/0 to 40/60, and morepreferably from 100/0 to 50/50 in terms of a molar ratio (compound(A)/other acid generating agent).

As such a photo acid generating agent that can be used jointly,photoinitiators of photo cationic polymerization, photoinitiators ofphoto radical polymerization, light fading agents of dyes, lightdiscoloring agents, known compounds capable of generating an acid byirradiation with the actinic ray or the radiation, which are used inmicro resists, etc., and mixtures thereof can be adequately chosen andused.

Examples thereof include diazonium salts, phosphonium salts, sulfoniumsalts, iodonium salts, imide sulfonates, oxime sulfonates, diazodisulfones, disulfones, and o-nitrobenzyl sulfonate.

Also, compounds in which a group or compound capable of generating anacid by irradiation with the actinic ray or the radiation is introducedinto the principal chain or the side chain of a polymer, for example,compounds described in U.S. Pat. No. 3,849,137, German Patent No.3,914,407, JP-A-63-26653, JP-A-55-164824, JP-A-62-69263, JP-A-63-146038,JP-A-63-163452, JP-A-62-153853, and JP-A-63-146029, can be used.

Further, compounds capable of generating an acid by light described inU.S. Pat. No. 3,779,778 and European Patent No. 126,712 can be used.

Of the compounds that are decomposed by irradiation with the actinic rayor the radiation to generate an acid, which may be used jointly,compounds represented by the following general formulae (ZI), (ZII) and(ZIII) are preferable.

In the foregoing general formula (ZI), R₂₀₁, R₂₀₂, and R₂₀₃ eachindependently represents an organic group.

The organic group as R₂₀₁, R₂₀₂, and R₂₀₃ generally has from 1 to 30carbon atoms, and preferably from 1 to 20 carbon atoms.

Also, two of R₂₀₁, R₂₀₂, and R₂₀₃ may be taken together to form a ringstructure. The ring may contain an oxygen atom, a sulfur atom, an esterbond, an amide bond, or a carbonyl group.

Examples of the group which two of R₂₀₁ to R₂₀₃ are taken together toform include an alkylene group (for example, a butylene group and apentylene group).

X⁻ represents a non-nucleophilic anion.

Examples of the non-nucleophilic anion as X⁻ include a sulfonic anion, acarboxylic anion, a sulfonylimide anion, a bis(alkylsulfonyl)imideanion, and a tris(alkylsulfonyl) methyl anion.

The non-nucleophilic anion as referred to herein means an anion having aremarkably low ability to cause nucleophilic reaction and an anioncapable of inhibiting decomposition with time due to intramolecularnucleophilic reaction. By this, stability with time of the resist isenhanced.

Examples of the sulfonic anion include an aliphatic sulfonic anion, anaromatic sulfonic anion, and a camphor sulfonic anion.

Examples of the carboxylic anion include an aliphatic carboxylic anion,an aromatic carboxylic anion, and an aralkyl carboxylic anion.

The aliphatic site in the aliphatic sulfonic anion may be an alkyl groupor a cycloalkyl group, and preferably an alkyl group having from 1 to 30carbon atoms or a cycloalkyl group having from 3 to 30 carbon atoms.Examples thereof include a methyl group, an ethyl group, a propyl group,an isopropyl group, an n-butyl group, an isobutyl group, a sec-butylgroup, a pentyl group, a neopentyl group, a hexyl group, a heptyl group,an octyl group, a nonyl group, a decyl group, an undecyl group, adodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group,a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecylgroup, an eucosyl group, a cyclopropyl group, a cyclopentyl group, acyclohexyl group, an adamantyl group, a norbornyl group, and boronylgroup.

The aromatic group in the aromatic sulfonic anion is preferably an arylgroup having from 6 to 14 carbon atoms, and examples thereof include aphenyl group, a tolyl group, and a naphthyl group.

Each of the alkyl group, the cycloalkyl group and the aryl group in theforegoing aliphatic sulfonic anion and aromatic sulfonic anion may havea substituent.

Examples of such a substituent include a nitro group, a halogen atom(for example, a fluorine atom, a chlorine atom, a bromine atom, and aniodine atom), a carboxyl group, a hydroxyl group, an amino group, acyano group, an alkoxy group (preferably, one having from 1 to 5 carbonatoms), a cycloalkyl group (preferably, one having from 3 to 15 carbonatoms), an aryl group (preferably, one having from 6 to 14 carbonatoms), an alkoxycarbonyl group (preferably, one having from 2 to 7carbon atoms), an acyl group (preferably, one having from 2 to 12 carbonatoms), and an alkoxycarbonyloxy group (preferably, one having from 2 to7 carbon atoms). With respect to the aryl group and ring structure whichthe respective groups have, an alkyl group (preferably, one having from1 to 15 carbon atom) can be further enumerated as the substituent.

As the aliphatic site in the aliphatic carboxylic anion, the same alkylgroup and cycloalkyl group as in the aliphatic sulfonic anion can beenumerated.

As the aryl group in the aromatic carboxylic anion, the same aryl groupas in the aromatic sulfonic anion can be enumerated.

The aralkyl group in the aralkyl carboxylic anion is preferably anaralkyl group having from 6 to 12 carbon atoms, and examples thereofinclude a benzyl group, a phenethyl group, a naphthylmethyl group, anaphthylethyl group, and a naphthylmethyl group.

Each of the alkyl group, the cycloalkyl group, the aryl group and thearalkyl group in the foregoing aliphatic carboxylic anion, aromaticcarboxylic anion and aralkyl carboxylic anion may have a substituent.Likewise the case of the aromatic sulfonic anion, examples of thesubstituent include a halogen atom, an alkyl group, a cycloalkyl group,an alkoxy group, and an alkylthio group.

Examples of the sulfonylimide anion include a saccharin anion.

The alkyl group in the bis (alkylsulfonyl) imide anion andtris(alkylsulfonyl)methyl anion is preferably an alkyl group having from1 to 5 carbon atoms, and examples thereof include a methyl group, anethyl group, a propyl group, an isopropyl group, an n-butyl group, anisobutyl group, a sec-butyl group, a pentyl group, and a neopentylgroup. Theses alkyl groups may have a substituent. Examples of thesubstituent include a halogen atom, a halogen atom-substituted alkylgroup, an alkoxy group, and an alkylthio group. Of these, a fluorineatom-substituted alkyl group is preferable.

Examples of other non-nucleophilic anion include phosphorus fluoride,boron fluoride, and antimony fluoride.

As the non-nucleophilic anion represented by X⁻, an aliphatic sulfonicanion in which the α-position of the sulfonic acid is substituted with afluorine atom, an aromatic sulfonic anion substituted with a fluorineatom or a fluorine atom-containing group, a bis(alkylsulfonyl)imideanion in which the alkyl group is substituted with a fluorine atom, anda tris (alkylsulfonyl)methyl anion in which the alkyl group issubstituted with a fluorine atom are preferable. As the non-nucleophilicanion, a perfluoro aliphatic sulfonic anion having from 4 to 8 carbonatoms and a fluorine atom-containing benzenesulfonic anion areespecially preferable; and a nonafluorobutanesulfonic anion, aperfluorooctanesulfonic anion, pentafluorobenzenesulfonic anion, and a3,5-bis (trifluoromethyl)benzenesulfonic anion are the most preferable.

As specific examples of the organic group as R₂₀₁, R₂₀₂, and R₂₀₃,corresponding groups in compounds (Z1-1), (Z1-2) and (Z1-3) describedlater can be enumerated.

Incidentally, compounds having the plural number of the structuresrepresented by the general formula (ZI) may be employed. For example,compounds having a structure in which at least one of R₂₀₁ to R₂₀₃ of acompound represented by the general formula (Z1) is bonded to at leastone of R₂₀₁ to R₂₀₃ of another compound represented by the generalformula (Z1) may be employed.

More preferably, the compounds (Z1-1), (Z1-2) and (Z1-3) described belowcan be enumerated as the compound (ZI).

The compound (Z-1) is an aryl sulfonium compound in which at least oneof R₂₀₁ to R₂₀₃ of the foregoing general formula (ZI) is an aryl group,that is, a compound in which the cation thereof is an aryl sulfonium.

In the aryl sulfonium compound, all of R₂₀₁ to R₂₀₃ may be an arylgroup, or a part of R₂₀₁ to R₂₀₃ may be an aryl group, with theremainder being an alkyl group or a cycloalkyl group.

Examples of the aryl sulfonium compound include triaryl sulfoniumcompounds, diarylalkyl sulfonium compounds, aryldialkyl sulfoniumcompounds, diarylcycloalkyl sulfonium compounds, and aryldicycloalkylsulfonium compounds.

As the aryl group of the aryl sulfonium compound, a phenyl group and anaphthyl group are preferable, and a phenyl group is more preferable. Inthe case where the aryl sulfonium compound has two or more aryl groups,the two or more aryl groups may be the same or different.

The alkyl group which the aryl sulfonium compound has as the need arisesis preferably a linear or branched alkyl group having from 1 to 15carbon atoms. Examples thereof include a methyl group, an ethyl group, apropyl group, an n-butyl group, a sec-butyl group, and a t-butyl group.

The cycloalkyl group which the aryl sulfonium compound has as the needarises is preferably a cycloalkyl group having from 3 to 15 carbonatoms. Examples thereof include a cyclopropyl group, a cyclobutyl group,and a cyclohexyl group.

The aryl group, the alkyl group, and the cycloalkyl group as R₂₀₁ toR₂₀₃ may each have an alkyl group (for example, one having from 1 to 15carbon atoms), a cycloalkyl group (for example, one having from 3 to 15carbon atoms), an aryl group (for example, one having from 6 to 14carbon atoms), an alkoxy group (for example, one having from 1 to 15carbon atoms), a halogen atom, a hydroxyl group, or a phenylthio groupas a substituent. As the substituent, a linear or branched alkyl grouphaving from 1 to 12 carbon atoms, a cycloalkyl group having from 3 to 12carbon atoms, and a linear, branched or cyclic alkoxy group having from1 to 12 carbon atoms are preferable; and an alkyl group having from 1 to4 carbon atoms and an alkoxy group having from 1 to 4 carbon atoms aremore preferable. The substituent may be substituted on any one of threeR₂₀₁ to R₂₀₃ or may be substituted on all of three R₂₀₁ to R₂₀₃. Also,in the case where R₂₀₁ to R₂₀₃ are an aryl group, it is preferable thatthe substituent is substituted at the p-position of the aryl group.

Next, the compound (Z1-2) will be described below.

The compound (Z1-2) is a compound in the case where in the formula (ZI),R₂₀₁ to R₂₀₃ each independently represents an aromatic ring-free organicgroup. The aromatic ring as referred to herein includes aromatic ringscontaining a hetero atom.

The aromatic ring-free organic group as R₂₀₁ to R₂₀₃ generally has from1 to 30 carbon atoms, and preferably from 1 to 20 carbon atoms.

R₂₀₁ to R₂₀₃ are each independently preferably an alkyl group, acycloalkyl group, an allyl group, or a vinyl group; more preferably alinear or branched 2-oxoalkyl group, a 2-oxocycloalkyl group, or analkoxycarbonylmethyl group; and most preferably a linear or branched2-oxoalkyl group.

The alkyl group as R₂₀₁ to R₂₀₃ is preferably a linear or branched alkylgroup having from 1 to 10 carbon atoms, and examples thereof include amethyl group, an ethyl group, a propyl group, a butyl group, and apentyl group. The alkyl group is more preferably a 2-oxoalkyl group oran alkoxycarbonylmethyl group.

The cycloalkyl group as R₂₀₁ to R₂₀₃ is preferably a cycloalkyl grouphaving from 3 to 10 carbon atoms, and examples thereof include acyclopentyl group, a cyclohexyl group, and a norbornyl group. Thecycloalkyl group is more preferably a 2-oxocycloalkyl group.

The 2-oxoalkyl group may be linear or branched and is preferably a grouphaving >C═O at the 2-position of the foregoing alkyl group.

The 2-oxocycloalkyl group is preferably a group having >C═O at the2-position of the foregoing cycloalkyl group.

The alkoxy group in the alkxoycarbonylmethyl group is preferably analkoxy group having from 1 to 5 carbon atoms (for example, a methoxygroup, an ethoxy group, a propoxy group, a butoxy group, and apentyloxy-group).

Each of R₂₀₁ to R₂₀₃ may be further substituted with a halogen atom, analkoxy group (for example, one having from 1 to 5 carbon atoms), ahydroxyl group, a cyano group, or a nitro group.

The compound (Z1-3) is a compound represented by the following generalformula (Z1-3) and is a compound having an phenacyl sulfonium saltstructure.

In the general formula (Z1-3), R_(1c) to R_(5c) each independentlyrepresents a hydrogen atom, an alkyl group, a cycloalkyl group, analkoxy group, or a halogen atom.

R_(6c) and R_(7c) each independently represents a hydrogen atom, analkyl group, or a cycloalkyl group.

R_(x) and R_(y) each independently represents an alkyl group, acycloalkyl group, an allyl group, or a vinyl group.

Two or more of R_(1c) to R_(5c), R_(6c) and R_(7c), or R_(x) and R_(y)may be taken together to form a ring structure. This ring structure maycontain an oxygen atom, a sulfur atom, an ester bond, or an amide bond.Examples of the group which two or more of R_(1c) to R_(5c), R_(6c) andR_(7c), or R_(x) and R_(y) are taken together to form include a butylenegroup and a pentylene group.

Zc⁻ represents a non-nucleophilic anion, and the same non-nucleophilicanion as in the general formula (ZI) can be enumerated.

The alkyl group as R_(1c) to R_(7c) may be linear or branched, andexamples thereof include an alkyl group having from 1 to 20 carbonatoms, and preferably a linear or branched alkyl group having from 1 to12 carbon atom (for example, a methyl group, an ethyl group, a linear orbranched propyl group, a linear or branched butyl group, and a linear orbranched pentyl group).

The cycloalkyl group is preferably a cycloalkyl group having from 3 to 8carbon atoms (for example, a cyclopentyl group and a cyclohexyl group).

The alkoxy group as R_(1c) to R₅, may be linear, branched or cyclic, andexamples thereof include an alkoxy group having from 1 to 10 carbonatoms, and preferably a linear or branched alkoxy group having from 1 to5 carbon atoms (for example, a methoxy group, an ethoxy group, a linearor branched propoxy group, a linear or branched butoxy group, and alinear or branched pentoxy group), and a cyclic alkoxy group having from3 to 8 carbon atoms (for example, a cyclopentyloxy group and acyclohexyloxy group).

Preferably, any one of R_(1c) to R₅, is a leaner or branched alkylgroup, a cycloalkyl group, or a linear, branched or cyclic alkoxy group;and more preferably, the sum of carbon atoms of R_(1c) to R_(5c) is from2 to 15. In this regard, the solvent solubility is more enhanced so thatthe generation of particles is inhibited at the time of storage.

The alkyl group and the cycloalkyl group as R_(x) and R_(y) are the sameas the alkyl group and the cycloalkyl group as R_(1c) to R_(7c),respectively. Of these, a 2-oxoalkyl group, a 2-oxocycloalkyl group, andan alkoxycarbonylmethyl group are more preferable.

As the 2-oxoalkyl group and the 2-oxocycloalkyl group, groupshaving >C═O at the 2-position of each of the alkyl group and thecycloalkyl group as R_(1c) to R_(7c) can be enumerated.

The alkoxy group in the alkoxycarbonylmethyl group is the same as thealkoxy group as R_(1c) to R_(5c).

R_(x) and R_(y) are preferably an alkyl group or a cycloalkyl group eachhaving 4 or more carbon atoms, more preferably an alkyl group or acycloalkyl group each having 6 or more carbon atoms, and furtherpreferably an alkyl group or a cycloalkyl group each having 8 or morecarbon atoms.

In the general formulae (ZII) and (ZIII), R₂₀₄ to R₂₀₇ eachindependently represents an aryl group, an alkyl group, or a cycloalkylgroup.

The aryl group as R₂₀₄ to R₂₀₇ is preferably a phenyl group or anaphthyl group, and more preferably a phenyl group.

The alkyl group as R₂₀₄ to R₂₀₇ is preferably a linear or branched alkylgroup having from 1 to 10 carbon atoms, and examples thereof include amethyl group, an ethyl group, a propyl group, a butyl group, and apentyl group.

The cycloalkyl group as R₂₀₄ to R₂₀₇ is preferably a cycloalkyl grouphaving from 3 to 10 carbon atoms, and examples thereof include acyclopentyl group, a cyclohexyl group, and a norbornyl group.

Examples of the substituent which R₂₀₄ to R₂₀₇ may have include an alkylgroup (for example, one having from 1 to 15 carbon atoms), a cycloalkylgroup (for example, one having from 3 to 15 carbon atoms), an aryl group(for example, one having from 6 to 15 carbon atoms), an alkoxy group(for example, one having from 1 to 15 carbon atoms), a halogen atom, ahydroxyl group, and a phenylthio group.

X⁻ represents a non-nucleophilic anion, and the same non-nucleophilicanion as X⁻ in the general formula (ZI) can be enumerated.

Examples of the compounds capable of generating an acid by irradiationwith the actinic ray or the radiation, which may be used jointly,include compounds represented by the following general formulae (ZIV),(ZV) and (ZVI).

In the general formulae (ZIV) to (ZVI), Ar₃ and Ar₄ each independentlyrepresents an aryl group.

R₂₀₆, R₂₀₇, and R₂₀₈ each independently represents an alkyl group or anaryl group.

A represents an alkylene group, an alkenylene group, or an arylenegroup.

Of the compounds capable of generating an acid by irradiation with theactinic ray or the radiation, which may be used jointly, the compoundsrepresented by the general formulae (ZI) to (ZIII) are more preferable.

Also, as the compound capable of generating an acid by irradiation withthe actinic ray or the radiation, which may be used jointly, a compoundcapable of generating a sulfonic acid having one sulfonic group ispreferable; a compound capable of generating a monovalent perfluoroaliphatic sulfonic acid and a compound capable of generating an aromaticsulfonic acid substituted with a fluorine atom or a fluorineatom-substituted group are more preferable.

Of the compounds capable of generating an acid by irradiation with theactinic ray or the radiation, which may be used jointly, the followingcompounds are especially preferable.

[2] (B) Resin, the solubility of which in an alkaline developerincreases by the action of an acid (hereinafter sometimes referred to as“component (B)”):

The resin, the solubility of which in an alkaline developer increases bythe action of an acid, and which is used in the positive photosensitivecomposition of the invention, is a resin having a group capable of beingdecomposed by an acid (hereinafter sometimes referred to as “aciddecomposable group”) in the principal chain or the side chain or boththe principal chain and the side chain of the resin. Above all, a resinhaving a group capable of being decomposed by an acid in the side chainis more preferable.

The group capable of being decomposed by an acid is preferably a groupresulting from substitution of the hydrogen atom of a —COOH group or an—OH group with a group capable of being eliminated by an acid.

In the invention, it is preferable that the acid decomposable group isan acetal group or a tertiary ester group.

In the case where a group capable of being decomposed by an acid isbonded as the side chain, the matrix resin is an alkali-soluble resinhaving an —OH or —COOH group in the side chain. For example,alkali-soluble resins described later can be enumerated.

The alkali dissolution rate of such an alkali-soluble resin ispreferably 170 A/sec or more, and especially preferably 330 A/sec ormore (“A” means an angstrom) as measured (at 23° C.) in 0.261Ntetramethylammonium hydroxide (TMAH).

From this viewpoint, alkali-soluble resins having a hydroxystyrenestructural unit, such as o-, m- or p-poly (hydroxystyrene) andcopolymers thereof, hydrogenated poly (hydroxystyrene), halogen- oralkyl-substituted poly (hydroxystyrene), partly O-alkylated orO-acylated products of poly(hydroxystyrene), a styrene-hydroxystyrenecopolymer, an α-methylstyrene-hydroxystyrene copolymer, and hydrogenatednovolak resins, are especially preferable as the alkali-soluble resin.

As the preferred acid decomposable group-containing repeating unit inthe invention, t-butoxycarbonyloxystyrene, a 1-alkoxyethoxystyrene, anda (meth)acrylic acid tertiary alkyl ester can be enumerated.

The component (B) to be used in the invention can be obtained byreacting the alkali-soluble resin with a precursor of a group capable ofbeing decomposed by an acid, or copolymerizing an alkali-soluble resinmonomer having a group capable of being decomposed by an acid bondedthereto and a variety of monomers as disclosed in European Patent No.254853, JP-A-2-25850, JP-A-3-223860 and JP-A-4-251259.

Specific examples of the component (B) to be used in the invention willbe given below, but it should not be construed that the invention islimited thereto.

-   p-t-Butoxystyrene/p-hydroxystyrene copolymer-   p-(t-Butoxycarbonyloxy)styrene/p-hydroxystyrene copolymer-   p-(t-Butoxycarbonylmethyloxy)styrene/p-hydroxystyrene copolymer-   4-(t-Butoxycarbonylmethyloxy)-3-methylstyrene/4-hydro    xy-3-methylstyrene copolymer-   p-(t-Butoxycarbonylmethyloxy)styrene/p-hydroxystyrene (10%    hydrogenated product) copolymer-   m-(t-Butoxycarbonylmethyloxy)styrene/m-hydroxystyrene copolymer-   o-(t-Butoxycarbonylmethyloxy)styrene/o-hydroxystyrene copolymer-   p-(Cumyloxycarbonylmethyloxy)styrene/p-hydroxystyrene copolymer-   Cumyl methacrylate/methyl methacrylate copolymer-   4-t-Butoxycarbonylstyrene/dimethyl maleate copolymer-   Benzyl methacrylate/tetrahydropyranyl methacrylate copolymer-   p-(t-Butoxycarbonylmethyloxy)styrene/p-hydroxystyrene/styrene    copolymer-   p-t-Butoxystyrene/p-hydroxystyrene/fumaronitrile copolymer-   t-Butoxystyrene/hydroxyethyl methacrylate copolymer-   Styrene/N-(4-hydroxyphenyl)maleimide/N-(4-t-butoxycar    bonyloxyphenyl)maleimide copolymer-   p-Hydroxystyrene/t-butyl methacrylate copolymer-   Styrene/p-hydroxystyrene/t-butyl methacrylate copolymer-   p-Hydroxystyrene/t-butyl methacrylate copolymer-   Styrene/p-hydroxystyrene/t-butyl acrylate copolymer-   p-(t-Butoxycarbonylmethyloxy)styrene/p-hydroxystyrene/N-methylmaleimide    copolymer-   t-Butyl methacrylate/1-adamantylmethyl methacrylate copolymer-   p-Hydroxystyrene/t-butyl acrylate/p-acetoxystyrene copolymer-   p-Hydroxystyrene/t-butyl acrylate/p-(t-butoxycarbonyloxy)styrene    copolymer-   p-Hydroxystyrene/t-butyl    acrylate/p-(t-butoxycarbonylmethyloxy)styrene copolymer

In the foregoing specific examples, the symbol “tBu” represents at-butyl group.

The content of the group capable of being decomposed by an acid isexpressed by [B/(B+S)] wherein B represents the number of the groupcapable of being decomposed by an acid in the resin, and S representsthe number of the alkali-soluble group not protected by a group capableof being eliminated by an acid. The content is preferably from 0.01 to0.7, more preferably from 0.05 to 0.50, and further preferably from 0.05to 0.40.

(Ba) Resin having a monocyclic or polycyclic alicyclic hydrocarbonstructure, the solubility of which in an alkaline developer increases bythe action of an acid:

In the case where the positive photosensitive composition of theinvention is irradiated with an ArF excimer laser, it is preferable thatthe resin as the component (B) is a resin having a monocyclic orpolycyclic alicyclic hydrocarbon structure, the solubility of which inan alkaline developer increases by the action of an acid.

As the resin having a monocyclic or polycyclic alicyclic hydrocarbonstructure, the solubility of which in an alkaline developer increases bythe action of an acid (this resin will be hereinafter sometimes referredto as “alicyclic hydrocarbon based acid decomposable resin”), a resinhaving at least one member selected from the group consisting of arepeating unit having a partial structure containing an alicyclichydrocarbon represented by any one of the following general formulae(pI) to (pVI) and a repeating unit represented by the following generalformula (II-AB).

In the formulae, R₁₁ represents a methyl group, an ethyl group, ann-propyl group, an isopropyl group, an n-butyl group, an isobutyl group,or a sec-butyl group.

Z represents an atomic group necessary for forming an alicyclichydrocarbon group together with a carbon atom.

R₁₂ to R₁₆ each independently represents a linear or branched alkylgroup having from 1 to 4 carbon atom or an alicyclic hydrocarbon group,with proviso that at least one of R₁₂ to R₁₄ and any one of R₁₅ and R₁₆represent an alicyclic hydrocarbon group.

R₁₇ to R₂₁ each independently represents a hydrogen atom, a linear orbranched alkyl group having from 1 to 4 carbon atoms or an alicyclichydrocarbon group, with proviso that at least one of R₁₇ to R₂₁represents an alicyclic hydrocarbon group and that any one of R₁₉ andR₂, represents a linear or branched alkyl group having from 1 to 4carbon atoms or an alicyclic hydrocarbon group.

R₂₂ to R₂₅ each independently represents a hydrogen atom, a linear orbranched alkyl group having from 1 to 4 carbon atoms or an alicyclichydrocarbon group, with proviso that at least one of R₂₂ to R₂₅represents an alicyclic hydrocarbon group and that R₂₃ and R₂₄ may betaken together to form a ring.

In the general formula (II-AB), R₁₁′ and R₁₂′ each independentlyrepresents a hydrogen atom, a cyano group, a halogen atom, or an alkylgroup.

Z′ represents an atomic group for forming an alicyclic structure, whichcontains bonded two carbon atoms (C—C).

Also, the foregoing general formula (II-AB) is further preferably thefollowing general formula (II-A) or (II-B).

In the formulae (II-A) and (II-B), R₁₃′ to R₁₆′ each independentlyrepresents a hydrogen atom, a halogen atom, a cyano group, —COOH,—COOR₅, a group capable of being decomposed by an acid,—C(═O)—X-A′-R₁₇′, an alkyl group, or a cyclic hydrocarbon group.

Here, R₅ represents an alkyl group, a cyclic hydrocarbon group, or thefollowing —Y group.

X represents an oxygen atom, a sulfur atom, —NH—, —NHSO₂—, or —NHSO₂NH—.

A′ represents a single bond or a divalent connecting group.

R₁₇′ represents —COOH, —COOR₅, —CN—, a hydroxyl group, an alkoxy group,—CO—NH—R₆, —CO—NH—SO₂—R₆, or the following —Y group.

R₆ represents an alkyl group or a cyclic hydrocarbon group.

Also, at least two of R₁₃′ to R₁₆′ may be taken together to form a ring.

n represents 0 or 1.

—Y group:

In the —Y group, R₂₁′ to R₃₀′ each independently represents a hydrogenatom or an alkyl group.

a and b each represents 1 or 2.

In the general formulae (pI) to (pVI), the alkyl group as R₁₂ to R₂₅ ispreferably a linear or branched alkyl group having from 1 to 4 carbonatoms. Examples of the alkyl group as R₁₂ to R₂₅ include a methyl group,an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group,an isobutyl group, a sec-butyl group, and a t-butyl group.

The foregoing alkyl group may further have a substituent. Examples ofthe substituent which the alkyl group may have include an alkoxy grouphaving from 1 to 4 carbon atoms, a halogen atom (for example, a fluorineatom, a chlorine atom, a bromine atom, and an iodine atom), an acylgroup, an acyloxy group, a cyano group, a hydroxyl group, a carboxygroup, an alkoxycarbonyl group, and a nitro group.

The alicyclic hydrocarbon group as R₁₂ to R₂₅ or the alicyclichydrocarbon group which Z forms together with the carbon atom may bemonocyclic or polycyclic. Specifically, groups having a monocyclic,bicyclic, tricyclic or tetracyclic structure having 5 or more carbonatoms can be enumerated. The number of carbon atoms is preferably from 6to 30, and especially preferably from 7 to 25. These alicyclichydrocarbon groups may have a substituent.

Preferred examples of the alicyclic hydrocarbon group include anadamantyl group, a noradamantyl group, a decalin residue, atricyclodecanyl group, a tetracyclododecanyl group, a norbornyl group, acedrol group, a cyclohexyl group, a cycloheptyl group, a cyclooctylgroup, a cyclodecanyl group, and a cyclododecanyl group. Of these, anadamantyl group, a decalin residue, a norbornyl group, a cedrol group, acyclohexyl group, a cycloheptyl group, a cyclooctyl group, acyclodecanyl group, and a cyclododecanyl group are more preferable.

The alicyclic hydrocarbon group may further have a substituent. Examplesof the substituent of the alicyclic hydrocarbon group include an alkylgroup, a halogen atom, a hydroxyl group, an alkoxy group, a carboxylgroup, and an alkoxycarbonyl group. As the alkyl group, lower alkylgroups such as a methyl group, an ethyl group, a propyl group, anisopropyl group, and a butyl group are preferable. More preferably, thealkyl group is selected from the group consisting of a methyl group, anethyl group, a propyl group, and an isopropyl group. As the alkoxygroup, those having from 1 to 4 carbon atoms, such as a methoxy group,an ethoxy group, a propoxy group, and a butoxy group can be enumerated.The foregoing alkyl group, alkoxy group and alkoxycarbonyl group mayfurther have a substituent. Examples of the substituent which the alkylgroup, the alkoxy group, or the alkoxycarbonyl group may have include ahydroxyl group, a halogen atom, and an alkoxy group.

The structures represented by the general formulae (pI) to (pVI) in theforegoing resin can be used for protecting an alkali-soluble group. Asthe alkali-soluble group, various groups known in this technical fieldare enumerated.

Specifically, a carboxylic group, a sulfonic group, a phenol group, anda thio group are enumerated. Of these, a carboxylic group and a sulfonicgroup are preferable.

As the alkali-soluble group protected by any one of the structuresrepresented by the general formulae (pI) to (pVI) in the foregoingresin, structures resulting from substitution of a hydrogen atom of acarboxyl group with any one of the structures of the general formulae(pI) to (pVI) are preferably enumerated.

As a repeating unit having an alkali-soluble group protected by any oneof the structures represented by the general formulae (pI) to (pVI), arepeating unit represented by the following general formula (pA) ispreferable.

Here, R represents a hydrogen atom, a halogen atom, or a linear orbranched alkyl group having from 1 to 4 carbon atoms. Plural R may bethe same or different.

A represents a single group or a combination of two or more groupsselected from the group consisting of a single bond, an alkylene group,an ether group, a thioether group, a carbonyl group, an ester group, anamide group, a sulfonamide group, a urethane group, and a urea group.

Ra represents any one group of the foregoing formulae (pI) to (pVI).

The repeating unit represented by the general formula (pA) is mostpreferably a repeating unit by a 2-alkyl-2-adamantyl (meth) acrylate ora dialkyl (1-adamantyl) methyl (meth)acrylate.

Specific examples of the repeating unit represented by the generalformula (pA) will be given below.

In the foregoing general formula (II-AB), R₁₁′ and R₁₂′ eachindependently represents a hydrogen atom, a cyano group, a halogen atom,or an alkyl group.

Z′ represents an atomic group for forming an alicyclic structure, whichcontains bonded two carbon atoms (C—C).

Examples of the halogen atom in the foregoing R₁₁′ and R₁₂′ include achlorine atom, a bromine atom, a fluorine atom, and an iodine atom.

As the alkyl group in the foregoing R₁₁′ and R₁₂′, a linear or branchedalkyl group having from 1 to 10 carbon atoms is preferable; a linear orbranched alkyl group having from 1 to 6 carbon atoms is more preferable;and a methyl group, an ethyl group, a propyl group, an isopropyl group,an n-butyl group, an isobutyl group, a sec-butyl group, and a t-butylgroup are further preferable.

Examples of a substituent which the foregoing alkyl group may furtherhave include a hydroxyl group, a halogen atom, a carboxyl group, analkoxy group, an acyl group, a cyano group, and an acyloxy group.Examples of the halogen atom include a chlorine atom, a bromine atom, afluorine atom, and an iodine group. Examples of the alkoxy group includeone having from 1 to 4 carbon atoms, such as a methoxy group, an ethoxygroup, a propoxy group, and a butoxy group. Examples of the acyl groupinclude a formyl group and an acetyl group. Examples of the acyloxygroup include an acetoxy group.

The atomic group for forming the alicyclic structure of the foregoing Z′is an atomic group of forming a repeating unit of an optionallysubstituted alicyclic hydrocarbon in the resin. Above all, an atomicgroup for forming a bridged alicyclic structure of forming a repeatingunit of a bridged alicyclic hydrocarbon is preferable.

As a skeleton of the alicyclic hydrocarbon to be formed, the samealicyclic hydrocarbon groups as in R₁₁ to R₂₅ in the general formulae(pI) to (pVI) are enumerated.

The foregoing alicyclic hydrocarbon skeleton may have a substituent. Asthe substituent, R₁₃′ to R₁₆′ in the foregoing general formula (II-A) or(II-B) can be enumerated.

Of the foregoing repeating units having a bridged alicyclic hydrocarbon,the repeating unit represented by the foregoing general formula (II-A)or (II-B) is further preferable.

In the alicyclic hydrocarbon based acid decomposable resin according tothe invention, the acid decomposable group may be contained in theforegoing —C(═O)—X-A′-R₁₇′ or may be contained as a substituent of Z′ ofthe general formula (II-AB).

The structure of the acid decomposable group is represented by—C(═O)—X₁—R₀.

In the formula, examples of R₀ include a tertiary alkyl group such as at-butyl group and a t-amyl group, a 1-alkoxyethyl group such as anisoboronyl group, a 1-ethoxyethyl group, a 1-butoxyethyl group, a1-isobutoxyethyl group, and a 1-cyclohexyloxyethyl group, analkoxymethyl group such as a 1-methoxymethyl group and a 1-ethoxymethylgroup, a 3-oxoalkyl group, a tetrahydropyranyl group, atetrahydrofuranyl group, a trialkylsilyl ester group, a 3-oxocyclohexylester group, a 2-methyl-2-adamantyl group, and a mevalonic lactoneresidue. X₁ is synonymous with the foregoing X.

Examples of the halogen atom in the foregoing R₁₃′ to R₁₆′ include achlorine atom, a bromine atom, a fluorine atom, and an iodine atom.

The alkyl group in the foregoing R₁₃′ to R₁₆′, R₅, R₆, and R₂₁′ to R₃₀′is preferably a linear or branched alkyl group having from 1 to 10carbon atoms, more preferably a linear or branched alkyl group havingfrom 1 to 6 carbon atoms, and further preferably a methyl group, anethyl group, a propyl group, an isopropyl group, an n-butyl group, anisobutyl group, a sec-butyl group, or a t-butyl group.

Examples of the alicyclic hydrocarbon group in the foregoing R₁₃′ toR₁₆′, R₅, and R₆ include an alicyclic alkyl group and a bridgedhydrocarbon, for example, a cyclopropyl group, a cyclopentyl group, acyclohexyl group, an adamantly group, a 2-methyl-2-adamntyl group, anorbornyl group, a boronyl group, an isoboronyl group, a tricyclodecanylgroup, a dicyclopentenyl group, a norborane epoxy group, a mentyl group,an isomentyl group, a neomentyl group, and a tetracyclododecanyl group.

Examples of the ring which at least two of the foregoing R₁₃′ to R₁₆′are taken together to form include a ring having from 5 to 12 carbonatoms, such as cyclopentene, cyclohexene, cycloheptane, and cyclooctane.

Examples of the alkoxy group in the foregoing R₁₇′ include one havingfrom 1 to 4 carbon atoms, such as a methoxy group, an ethoxy group, apropoxy group, and a butoxy group.

Examples of a substituent which the foregoing alkyl group, alicyclichydrocarbon group or alkoxy group may further have include a hydroxylgroup, a halogen atom, a carboxyl group, an alkoxy group, an acyl group,a cyano group, an acyloxy group, an alkyl group, and an alicyclichydrocarbon group. Examples of the halogen atom include a chlorine atom,a bromine atom, a fluorine atom, and an iodine atom. Examples of thealkoxy group include one having from 1 to 4 carbon atoms, such as amethoxy group, an ethoxy group, a propoxy group, and a butoxy group.Examples of the acyl group include a formyl group and an acetyl group.Examples of the acyloxy group include an acetoxy group.

Also, as the alkyl group and the cyclic hydrocarbon group, thoseenumerated above are enumerated.

The divalent connecting group of the foregoing A′ is one member or acombination of two or more members selected from the group consisting ofan alkylene group, an ether group, a thioether group, a carbonyl group,an ester group, an amide group, a sulfonamide group, a urethane group,and a urea group.

In the alicyclic hydrocarbon based acid decomposable resin according tothe invention, the group capable of being decomposed by the action of anacid can contain at least one repeating unit of a repeating unit havinga partial structure containing the alicyclic hydrocarbon represented byany one of the foregoing general formulae (pI) to (pVI), a repeatingunit represented by the general formula (II-AB), and a repeating unit ofcopolymerization component described later.

The respective substituent of R₁₃′ to R₁₆′ in the foregoing generalformula (II-A) or general formula (II-B) will each become a substituentof the atomic group for forming the alicyclic structure or the atomicgroup Z for forming the bridged alicyclic structure in the foregoinggeneral formula (II-AB).

Specific examples of the repeating unit represented by the foregoinggeneral formula (II-A) or general formula (II-B) will be given below,but it should not be construed that the invention is limited to thesespecific examples.

The alicyclic hydrocarbon based acid decomposable resin of the inventionpreferably has a lactone group, and more preferably a repeating unithaving a group having a lactone structure represented by the followinggeneral formula (Lc) or any one of the following general formulae (V-1)to (V-5). The group having a lactone structure may be bonded directly tothe principal chain.

In the general formula (Lc), Ra₁, Rb₁, Rc₁, Rd₁, and Re₁ eachindependently represents a hydrogen atom or an alkyl group; m and n eachindependently represents an integer of from 0 to 3; and (m+n) is from 2to 6.

In the general formulae (V-1) to (V-5), R_(1b) to R_(5b) eachindependently represents a hydrogen atom, an alkyl group, a cycloalkylgroup, an alkoxy group, an alkoxycarbonyl group, an alkylsulfonyliminogroup, or an alkenyl group, and two of R_(1b) to R_(5b) may be takentogether to form a ring.

As the alkyl group of Ra₁ to Re₁ in the general formula (Lc) and thealkyl group in the alkyl group, alkoxy group, alkoxycarbonyl group andalkylsulfonylimino group of R_(1b) to R_(5b) in the general formulae(V-1) to (V-5), an optionally substituted linear or branched alkyl groupis enumerated.

Examples of the repeating unit having a group having the lactonestructure represented by the general formula (Lc) or any one of thegeneral formulae (V-1) to (V-5) include a group in which at least one ofR₁₃′ to R₁₆′ in the foregoing general formula (II-A) or (II-B) isrepresented by the general formula (Lc) or any one of the generalformulae (V-1) to (V-5) (for example, a group in which R₅ of —COOR₅ isrepresented by the general formula (Lc) or any one of the generalformulae (V-1) to (V-5)) and a repeating unit represented by thefollowing general formula (AI).

In the general formula (AI), R_(b0) represents a hydrogen atom, ahalogen atom, or an alkyl group having from 1 to 4 carbon atoms.

Examples of the halogen atom of R_(b0) include a fluorine atom, achlorine atom, a bromine atom, and an iodine atom. R_(b0) is preferablya hydrogen atom.

A′ represents a single bond, an ether group, an ester group, a carbonylgroup, an alkylene group, or a divalent group comprising a combinationof these groups.

B₂ represents a group represented by the general formula (Lc) or any oneof the general formulae (V-1) to (V-5).

Specific examples of the repeating unit having a group having thelactone structure will be given below, but it should not be construedthat the invention is limited thereto.

The alicyclic hydrocarbon based acid decomposable resin of the inventionmay contain a repeating unit having a group represented by the followinggeneral formula (VII).

In the general formula (VII), R_(2c) to R_(4c) each independentlyrepresents a hydrogen atom or a hydroxyl group, with proviso that atleast one of R_(2c) to R_(4c) represents a hydroxyl group.

The group represented by the general formula (VII) is preferably adihydroxy body or a monohydroxy body, and more preferably a dihydroxybody.

Examples of the repeating unit having the group represented by thegeneral formula (VII) include one having a group in which at least oneof R₁₃′ to R₁₆′ in the foregoing general formula (II-A) or (II-B) isrepresented by the foregoing general formula (VII) (for example, a groupin which R₅ of —COOR₅ is represented by the general formula (VII)) and arepeating unit represented by the following general formula (AII).

In the general formula (AII), R_(1c) represents a hydrogen atom or amethyl group.

R_(2c) to R_(4c) each independently represents a hydrogen atom or ahydroxyl group, with proviso that at least one of R_(2c) to R_(4c)represents a hydroxyl group. It is preferable that two of R₂, to R₄,represent a hydroxyl group.

Specific examples of the repeating unit having the structure representedby the general formula (AII) will be given below, but it should not beconstrued that the invention is limited thereto.

The alicyclic hydrocarbon based acid decomposable resin of the inventionmay contain a repeating unit represented by the following generalformula (VIII).

In the foregoing general formula (VIII), Z₂ represents —O— or —N(R₄₁)—;R₄₁ represents a hydrogen atom, a hydroxyl group, an alkyl group, or—OSO₂—R₄₂; and R₄₂ represents an alkyl group, a cycloalkyl group, or acamphor residue. The alkyl group as R₄₁ and R₄₂ may be substituted witha halogen atom (preferably, a fluorine atom).

Specific examples of the repeating unit represented by the foregoinggeneral formula (VIII) will be given below, but it should not beconstrued that the invention is limited thereto.

In addition to the foregoing repeating structural units, the alicyclichydrocarbon based acid decomposable resin of the invention can containvarious repeating structural units for the purpose of adjusting the dryetching resistance, standard developer adaptability, adhesion to asubstrate, resist profile, and additional characteristics, such asresolving power, heat resistance, and sensitivity, that are generallyrequired in resists.

As such repeating structural units, repeating structural unitscorresponding to the following monomers can be enumerated. However, itshould not be construed that the invention is limited thereto.

In this way, it becomes possible to finely control performances requiredfor the alicyclic hydrocarbon based acid decomposable resin, especiallythe following performances.

-   (1) Dissolution in a coating solvent-   (2) Film forming property (glass transition point)-   (3) Alkali developability-   (4) Wear of film (hydrophilic/hydrophobic property and selection of    alkali-soluble group)-   (5) Adhesion to a substrate in the unexposed area-   (6) Dry etching resistance

Examples of such monomers include compounds having one additionpolymerizable unsaturated bond selected from acrylic esters, methacrylicesters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, andvinyl esters.

Besides, the monomers may be copolymerized so far as they are anaddition polymerizable unsaturated compound copolymerizable withmonomers corresponding the foregoing various repeating structural units.

In the alicyclic hydrocarbon based acid decomposable resin, the molarratio of the respective repeating structural units to be contained isadequately set up for the purpose of adjusting the dry etchingresistance of a resist, standard developer adaptability, adhesion to asubstrate, resist profile, and additional characteristics such asresolving power, heat resistance, and sensitivity that are generallyrequired in resists.

Preferred embodiments of the alicyclic hydrocarbon based aciddecomposable resin of the invention are as follows.

-   (1) One containing a repeating unit having a partial structure    containing an alicyclic hydrocarbon represented by any one of the    foregoing general formulae (pI) to (pVI) (side chain type).-   (2) One having a repeating unit represented by the general formula    (II-AB) (principal chain type). However, in (2), the following is    further enumerated.-   (3) One having a repeating unit represented by the general formula    (II-AB), a maleic anhydride derivative, and a (meth)-acrylate    structure (hybrid type).

In the alicyclic hydrocarbon based acid decomposable resin, the contentof the acid decomposable group-containing repeating unit is preferablyfrom 10 to 60% by mole, more preferably from 20 to 50% by mole, andfurther preferably from 25 to 40% by mole in the whole of the repeatingstructural units.

In the alicyclic hydrocarbon based acid decomposable resin, the contentof the repeating unit having a partial structure containing thealicyclic hydrocarbon represented by any one of the general formulae(pI) to (pVI) is preferably from 30 to 70% by mole, more preferably from35 to 65% by mole, and further preferably from 40 to 60% by mole in thewhole of the repeating structural units.

In the alicyclic hydrocarbon based acid decomposable resin, the contentof the repeating unit represented by the general formula (II-AB) ispreferably from 10 to 60% by mole, more preferably from 15 to 55% bymole, and further preferably from 20 to 50% by mole in the whole of therepeating structural units.

Also, the content of the repeating structural unit based on theforegoing additional copolymerization component monomer in the resin canbe adequately set up depending upon the desired performance of theresist. In general, it is preferably not more than 99% by mole, morepreferably not more than 90% by mole, and further preferably not morethan 80% by mole based on the total molar number of the repeatingstructural unit having a partial structure containing the alicyclichydrocarbon represented by any one of the foregoing general formulae(pI) to (pVI) and the repeating unit represented by the foregoinggeneral formula (II-AB).

When the composition of the invention is used for ArF exposure, it ispreferable in view of the transparency to ArF light that the resin doesnot have an aromatic group.

The alicyclic hydrocarbon based acid decomposable resin to be used inthe invention can be synthesized by the customary method (for example,radical polymerization). For example, as a general synthesis method,monomer seeds are charged in a reactor collectively or on the way ofreaction; if desired, the monomers are dissolved in a reaction solventsuch as ethers (for example, tetrahydrofuran, 1,4-dioxane, anddiisopropyl ether), ketones (for example, methyl ethyl ketone and methylisobutyl ketone), and ester solvents (for example, ethyl acetate) and asolvent capable of dissolving the composition of the invention asdescribed later (for example, propylene glycol monomethyl ether acetate)to form a uniform solution; and the solution is then initiated topolymerize using a commercially available radical initiator (forexample, azo based initiators and peroxides) in an inert gas atmospheresuch as nitrogen and argon upon heating as the need arises. If desired,the initiator is supplemented or added dividedly. After completion ofthe reaction, the reaction mixture is thrown into a solvent, and thedesired polymer is recovered by a powder or solid recovery method. Thereaction concentration is 20% by weight or more, preferably 30% byweight or more, and more preferably 40% by weight or more. The reactiontemperature is from 10° C. to 150° C., preferably from 30° C. to 120°C., and more preferably from 50 to 100° C.

(Baa) Resin having at least one repeating unit selected from a repeatingunit represented by the following general formula (1), a repeating unitrepresented by the following general formula (2), and a repeating unitrepresented by the following general formula (3), the solubility ofwhich in an alkaline developer increases by the action of an acid:

It is preferable that the alicyclic hydrocarbon based acid decomposableresin is a resin having at least one repeating unit selected from arepeating unit represented by the following general formula (1), arepeating unit represented by the following general formula (2), and arepeating unit represented by the following general formula (3), thesolubility of which in an alkaline developer increases by the action ofan acid (this resin will be hereinafter sometimes referred to as“alicyclic hydrocarbon based acid decomposable resin (Baa)”).

It is preferable that the alicyclic hydrocarbon based acid decomposableresin (Baa) has at least one repeating unit selected from a repeatingunit represented by the general formula (1), a repeating unitrepresented by the general formula (2), and a repeating unit representedby the general formula (3).

It is more preferable that the alicyclic hydrocarbon based aciddecomposable resin (Baa) has a repeating unit represented by the generalformula (1), a repeating unit represented by the general formula (2),and a repeating unit represented by the general formula (3).

By using the alicyclic hydrocarbon based acid decomposable resin (Baa),the positive photosensitive composition of the invention can ensure awide process window in the isolated line and dense pattern.

In the general formula (1), R represents a hydrogen atom or a methylgroup.

A represents a single bond or a connecting group.

ALG represents a group represented by any one of the following generalformulae (pI) to (pV).

In the general formulae (pI) to (pV), R₁₁ represents a methyl group, anethyl group, an n-propyl group, an isopropyl group, an n-butyl group, anisobutyl group, or a sec-butyl group.

Z represents an atomic group necessary for forming an alicyclichydrocarbon group together with a carbon atom.

R₁₂ to R₁₆ each independently represents a linear or branched alkylgroup having from 1 to 4 carbon atom or an alicyclic hydrocarbon group,with proviso that at least one of R₁₂ to R₁₄ and any one of R₁₅ and R₁₆represents an alicyclic hydrocarbon group.

R₁₇ to R₂₁ each independently represents a hydrogen atom, a linear orbranched alkyl group having from 1 to 4 carbon atoms or an alicyclichydrocarbon group, with proviso that at least one of R₁₇ to R₂₁represents an alicyclic hydrocarbon group and that any one of R₁₉ andR₂, represents a linear or branched alkyl group having from 1 to 4carbon atoms or an alicyclic hydrocarbon group.

R₂₂ to R₂₅ each independently represents a hydrogen atom, a linear orbranched alkyl group having from 1 to 4 carbon atoms or an alicyclichydrocarbon group, with proviso that at least one of R₂₂ to R₂₅represents an alicyclic hydrocarbon group and that R₂₃ and R₂₄ may betaken together to form a ring.

In the general formula (2), R_(1a) represents a hydrogen atom or amethyl group.

W₁ represents a single bond, or a single group or a combination of twoor more groups selected from the group consisting of an alkylene group,an ether group, a thioether group, a carbonyl group, and an ester group.

Lc represents a lactone residue represented by any one of the followinggeneral formulae (IV), (V-1) to (V-6) and (VI).

In the general formula (IV), R_(a1), R_(b1), R_(c1), R_(d1), and R_(e1)each independently represents a hydrogen atom or an alkyl group havingfrom 1 to 4 carbon atoms.

m and n each independently represents an integer of from 0 to 3, and(m+n) is from 2 to 6.

In the general formulae (V-1) to (V-6), R_(1b) to R_(5b) eachindependently represents a hydrogen atom, an alkyl group, a cycloalkylgroup, an alkenyl group, or COOR_(6b), wherein R_(6b) represents analkyl group, and two of R_(1b) to R_(5b) may be taken together to form aring.

In the general formula (3), R₃₀ represents a hydrogen atom or a methylgroup.

R₃₁ to R₃₃ each independently represents a hydrogen atom, a hydroxylgroup, or an alkyl group, with proviso that at least one of R₃₁ to R₃₃represents a hydroxyl group.

First of all, the general formula (1) will be described below.

The alicyclic hydrocarbon based acid decomposable resin (Baa) is aresin, the solubility of which in an alkaline developer increases by theaction of an acid (acid decomposable resin) and preferably has arepeating unit represented by the general formula (1), which is capableof generating a carboxyl group that is decomposed by the action of anacid and is an alkali-soluble group.

In the general formula (1), R represents a hydrogen atom or a methylgroup; A represents a single bond or a connecting group; and ALGrepresents a group represented by any one of the foregoing generalformulae (pI) to (pV).

The connecting group as A represents a single group or a combination oftwo or more groups selected from the group consisting of an alkylenegroup, an ether group, a thioether group, a carbonyl group, an estergroup, an amide group, a sulfonamide group, a urethane group, and a ureagroup. As the alkylene group in the foregoing A, a group represented bythe following formula can be enumerated.—[C(R_(b))(R_(c))]_(r)—

In the formula, R_(b) and R_(c) may be the same or different and eachrepresents a hydrogen atom, an alkyl group, a halogen atom, a hydroxylgroup, or an alkoxy group. As the alkyl group, lower alkyl groups suchas a methyl group, an ethyl group, a propyl group, an isopropyl group,and a butyl group are preferable. More preferably, the alkyl group isselected from a methyl group, an ethyl group, a propyl group, and anisopropyl group. Examples of the alkoxy group include ones having from 1to 4 carbon atoms, such as a methoxy group, an ethoxy group, a propoxygroup, and a butoxy group. Examples of the halogen atom include achlorine atom, a bromine atom, a fluorine atom, and an iodine atom. rrepresents an integer of from 1 to 10. The foregoing alkyl group andalkoxy group may have a substituent. Examples of the substituent whichthe alkyl group and the alkoxy group may have include a hydroxyl group,a halogen atom, and an alkoxy group (preferably, one having from 1 to 4carbon atoms).

In the general formulae (pI) to (pV), the alkyl group in R₁₂ to R₂₅represents a linear or branched alkyl group having from 1 to 4 carbonatoms, which may be substituted or unsubstituted. Examples of the alkylgroup include a methyl group, an ethyl group, an n-propyl group, anisopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group,and a t-butyl group.

Also, examples of a substituent which the foregoing alkyl group mayfurther have include an alkoxy group having from 1 to 4 carbon atoms, ahalogen atom (for example, a fluorine atom, a chlorine atom, a bromineatom, and an iodine atom), an acyl group, an acyloxy group, a cyanogroup, a hydroxyl group, a carboxy group, an alkoxycarbonyl group, and anitro group.

The alicyclic hydrocarbon group as R₁₂ to R₂₅ or the alicyclichydrocarbon group which Z forms together with the carbon atom may bemonocyclic or polycyclic. Specifically, groups having a monocyclic,bicyclic, tricyclic or tetracyclic structure having 5 or more carbonatoms can be enumerated. The number of carbon atoms is preferably from 6to 30, and especially preferably from 7 to 25. These alicyclichydrocarbon groups may have a substituent.

Examples of a structure of the alicyclic moiety in the alicyclichydrocarbon group will be given below.

In the invention, an adamantyl group, a noradamantyl group, a decalinresidue, a tricyclodecanyl group, a tetracyclododecanyl group, anorbornyl group, a cedrol group, a cyclohexyl group, a cycloheptylgroup, a cyclooctyl group, a cyclodecanyl group, and a cyclododecanylgroup are preferable as the foregoing alicyclic moiety. Of these, anadamantyl group, a decalin residue, a norbornyl group, a cedrol group, acyclohexyl group, a cycloheptyl group, a cyclooctyl group, acyclodecanyl group, a cyclododecanyl group, and a tricyclodecanyl groupare more preferable.

Examples of a substituent of these alicyclic hydrocarbon groups includean alkyl group, a halogen atom, a hydroxyl group, an alkoxy group, acarboxyl group, and an alkoxycarbonyl group.

As the alkyl group, lower alkyl groups such as a methyl group, an ethylgroup, a propyl group, an isopropyl group, and a butyl group arepreferable. Of these, a methyl group, an ethyl group, a propyl group,and an isopropyl group are more preferable.

As the alkoxy group, those having from 1 to 4 carbon atoms, such as amethoxy group, an ethoxy group, a propoxy group, and a butoxy group canbe enumerated.

The alkyl group and the alkoxy group may have a substituent. Examples ofa substituent which the alkyl group and the alkoxy group may haveinclude a hydroxyl group, a halogen atom, and an alkoxy group.

Incidentally, it is especially preferable that the general formula (1)is a repeating unit wherein A represents a single bond, and ALGrepresents a group represented by the following formula from thestandpoint that in observing the resulting profile by a scanningelectron microscope, the profile stability (SEM resistance) is good.

R₂₆ and R₂₇ each independently represents a linear or branched alkylgroup having from 1 to 4 carbon atoms.

Specific examples of a monomer corresponding to the repeating unitrepresented by the general formula (1) will be described below.

Next, the general formula (2) will be described below.

R_(1a) represents a hydrogen atom or a methyl group.

W₁ represents a single bond, or a single group or a combination of twoor more groups selected from the group consisting of an alkylene group,an ether group, a thioether group, a carbonyl group, and an ester group.Lc represents a lactone residue represented by any one of the foregoinggeneral formulae (IV), (V-1) to (V-6) and (VI):

As the alkylene group as W₁, a group represented by the followingformula can be enumerated.—[C(Rf)(Rg)]_(r1)—

In the foregoing formula, Rf and Rg may be the same or different andeach represents a hydrogen atom, an alkyl group, a halogen atom, ahydroxyl group, or an alkoxy group. As the alkyl group, lower alkylgroups such as a methyl group, an ethyl group, a propyl group, anisopropyl group, and a butyl group are preferable. More preferably, thealkyl group is selected from a methyl group, an ethyl group, a propylgroup, and an isopropyl group.

Examples of the alkoxy group include ones having from 1 to 4 carbonatoms, such as a methoxy group, an ethoxy group, a propoxy group, and abutoxy group.

Examples of the halogen atom include a chlorine atom, a bromine atom, afluorine atom, and an iodine atom. r₁ represents an integer of from 1 to10.

The foregoing alkyl group and alkoxy group may have a substituent.Examples of the substituent which the alkyl group and the alkoxy groupmay have include a hydroxyl group, a halogen atom, and an alkoxy group.

In the general formula (IV), examples of the alkyl group having from 1to 4 carbon atoms as R_(a1) to R_(e1) include a methyl group, an ethylgroup, a propyl group, an isopropyl group, an n-butyl group, an isobutylgroup, a sec-butyl group, and a t-butyl group.

In the general formulae (V-1) to (V-6), examples of the alkyl group asR_(1b) to R_(5b) include a linear or branched alkyl group, which mayhave a substituent. As the alkyl group as R_(1b) to R_(5b), a linear orbranched alkyl group having from 1 to 12 carbon atoms is preferable; alinear or branched alkyl group having from 1 to 10 carbon atoms is morepreferable; and a methyl group, an ethyl group, a propyl group, anisopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group,a t-butyl group, a pentyl group, a hexyl group, a heptyl group, an octylgroup, a nonyl group, and a decyl group are further preferable.

R_(6b) in COOR_(6b) as R_(1b) to R_(5b) in the general formulae (V-1) to(V-6) is preferably a linear or branched alkyl group having from 1 to 12carbon atoms; more preferably a linear or branched alkyl group havingfrom 1 to 10 carbon atoms; and further preferably a methyl group, anethyl group, a propyl group, an isopropyl group, an n-butyl group, anisobutyl group, a sec-butyl group, a t-butyl group, a pentyl group, ahexyl group, a heptyl group, an octyl group, a nonyl group, or a decylgroup.

As the cycloalkyl group in R_(1b) to R_(5b), those having from 3 to 8carbon atoms, such as a cyclopropyl group, a cyclopentyl group, acyclohexyl group, a cycloheptyl group, and a cyclooctyl group, arepreferable.

As the alkenyl group in R_(1b) to R_(5b), those having from 2 to 6carbon atoms, such as a vinyl group, a propenyl group, a butenyl group,and a hexenyl group, are preferable.

Also, as the ring which two of R_(1b) to R_(5b) are taken together toform, those having from 3 to 8 members, such as a cyclopropane ring, acyclobutane ring, a cyclopentane ring, a cyclohexane ring, and acyclooctane ring, are preferable.

Incidentally, R_(1b) to R_(5b) in the general formulae (V-1) to (V-6)may be connected to any carbon atom constituting the ring skeleton.

Also, examples of the substituent which the foregoing alkyl group,cycloalkyl group and alkenyl group may have include an alkoxy grouphaving from 1 to 4 carbon atoms, a halogen atom (for example, a fluorineatom, a chlorine atom, a bromine atom, and an iodine atom), an acylgroup having from 2 to 5 carbon atoms, an acyloxy group having from 2 to5 carbon atoms, a cyano group, a hydroxyl group, a carboxy group, analkoxycarbonyl group having from 2 to 5 carbon atoms, and a nitro group.

Specific examples of the repeating unit having a group having thelactone structure represented by any one of the general formulae (IV),(V-1) to (V-6) and (VI) will be given below, but it should not beconstrued that the invention is limited thereto.

First of all, specific examples of the repeating unit of the generalformula (2) having the lactone structure represented by the generalformula (IV) will be given below, but it should not be construed thatthe invent-ion is limited thereto.

Next, specific examples of the repeating unit of the general formula (2)having the lactone structure represented by any one of the generalformulae (V-1) to (V-6) will be given below, but it should not beconstrued that the invention is limited thereto.

Specific examples of the repeating unit of the general formula (2)having the lactone structure represented by the general formula (VI)will be given below.

Next, the repeating unit represented by the general formula (3) will bedescribed below.

In the general formula (3), R₃₀ represents a hydrogen atom or a methylgroup.

R₃₁ to R₃₃ each independently represents a hydrogen atom, a hydroxylgroup, or an alkyl group, with proviso that at least one of R₃₁ to R₃₃represents a hydroxyl group.

As the alkyl group of R₃₁ to R₃₃, an alkyl group having from 1 to 5carbon atoms is preferable, and examples thereof include a methyl group,an ethyl group, a propyl group, an isopropyl group, an n-butyl group, anisobutyl group, a sec-butyl group, and a t-butyl group.

In the repeating unit represented by the general formula (3), it ispreferable that one or two of R₃₁ to R₃₃ represent a hydroxyl group, andit is especially preferable that two of R₃₁ to R₃₃ represent a hydroxylgroup.

Specific examples of the repeating unit represented by the generalformula (3) will be given below, but it should not be construed that theinvention is limited thereto.

In addition to the foregoing repeating structural units, the alicyclichydrocarbon based acid decomposable resin (Baa) can contain variousrepeating structural units for the purpose of adjusting the dry etchingresistance, standard developer adaptability, adhesion to a substrate,resist profile, and additional characteristics such as resolving power,heat resistance, and sensitivity that are generally required in resists.

As such repeating structural units, repeating structural unitscorresponding to the following monomers can be enumerated, but it shouldnot be construed that the invention is limited thereto.

In this way, it becomes possible to finely control performances requiredfor the resin, especially the following performances.

-   (1) Dissolution in a coating solvent-   (2) Film forming property (glass transition point)-   (3) Alkali developability-   (4) Wear of film (hydrophilic/hydrophobic property and selection of    alkali-soluble group)-   (5) Adhesion to a substrate in the unexposed area-   (6) Dry etching resistance

Examples of such monomers include compounds having one additionpolymerizable unsaturated bond selected from acrylic esters, methacrylicesters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, andvinyl esters.

Besides, the monomers may be copolymerized so far as they are anaddition polymerizable unsaturated compound copolymerizable withmonomers corresponding the foregoing various repeating structural units.

In the alicyclic hydrocarbon based acid decomposable resin (Baa), themolar ratio of the respective repeating structural units to be containedis adequately set up for the purpose of adjusting the dry etchingresistance of a resist, standard developer adaptability, adhesion to asubstrate, resist profile, and additional characteristics, such asresolving power, heat resistance, and sensitivity that are generallyrequired in resists.

In the alicyclic hydrocarbon based acid decomposable resin (Baa), thecontent of the repeating unit represented by the general formula (1) ispreferably from 0 to 60% by mole, more preferably from 20 to 55% bymole, and further preferably from 25 to 50% by mole in the whole of therepeating structural units.

The content of the repeating unit of the general formula (2) ispreferably from 0 to 70% by mole, more preferably from 20 to 65% bymole, and further preferably from 25 to 60% by mole in the whole of therepeating structural units.

The content of the repeating unit of the general formula (3) ispreferably from 0 to 50% by mole, more preferably from 15 to 45% bymole, and further preferably from 20 to 40% by mole in the whole of therepeating structural units.

Also, the content of the repeating structural unit based on theforegoing additional copolymerization component monomer in the resin canbe adequately set up depending upon the desired performance of theresist. In general, it is preferably not more than 50% by mole, morepreferably not more than 40% by mole, and further preferably not morethan 30% by mole based on the total molar number of the general formulae(1) to (3).

When the composition of the invention is used for ArF exposure, it ispreferable in view of the transparency to ArF light that the alicyclichydrocarbon based acid decomposable resin (Baa) does not have anaromatic group.

The alicyclic hydrocarbon based acid decomposable resin (Baa) can besynthesized by the customary method (for example, radicalpolymerization). For example, as a general synthesis method, monomerseeds are charged in a reactor collectively or on the way of reaction;if desired, the monomers are dissolved in a reaction solvent such ascyclic ethers (for example, tetrahydrofuran and 1,4-dioxane), ketones(for example, methyl ethyl ketone, methyl isobutyl ketone, andcyclohexanone), and a solvent capable of dissolving the composition ofthe invention as described later (for example, propylene glycolmonomethyl ether acetate and propylene glycol monomethyl ether) to forma uniform solution; and the solution is then initiated to polymerizeusing a commercially available radical initiator (for example, azo basedinitiators and peroxides) in an inert gas atmosphere such as nitrogenand argon upon heating as the need arises. If desired, the initiator issupplemented or added dividedly. After completion of the reaction, thereaction mixture is thrown into a solvent, and the desired polymer isrecovered by a powder or solid recovery method. The reactionconcentration is 10% by weight or more, preferably 15% by weight ormore, and more preferably 20% by weight or more. The reactiontemperature is from 10° C. to 150° C., preferably from 30° C. to 120°C., and more preferably from 50 to 110° C.

The repeating structural units represented by the foregoing specificexamples may be used singly or in admixture for every repeatingstructural unit.

Also, in the invention, the alicyclic hydrocarbon based aciddecomposable resin (Baa) may be used singly or in admixture.

In the case where the composition of the invention is used an upperlayer resist of a multilayered resist, it is preferable that the resinas the component (B) has a silicon atom.

As the resin having a silicon atom, the solubility of which in analkaline developer increases by the action of an acid, any resin havinga silicon atom in at least one of the principal chain and the side chaincan be used. Examples of a resin having a siloxane structure in the sidechain thereof include copolymers of an olefin based monomer having asilicon atom in the side chain, maleic anhydride and a (meth)acrylicacid based monomer having an acid decomposable group in the side chain.

In the case where the positive photosensitive composition of theinvention is irradiated with an F₂ excimer laser, the resin as thecomponent (B) is preferably a resin having a structure in which afluorine atom is substituted in the principal chain and/or the sidechain of the polymer skeleton, which is decomposed by the action of anacid, whereby its solubility in an alkaline developer increases (thisresin will be hereinafter sometimes referred to as “fluorine-containingresin”); more preferably a resin containing a hydroxyl group substitutedwith a fluorine atom or a fluoroalkyl group at the 1-position or an aciddecomposable group-protected hydroxyl group substituted with a fluorineatom or a fluoroalkyl group at the 1-position; and most preferably aresin containing a hexafluoro-2-propanol structure or a structure inwhich the hydroxyl group of hexafluoro-2-propanol is protected by anacid decomposable group. By introducing a fluorine atom, it is possibleto enhance the transparency to far ultraviolet light, especially F₂ (157nm) light.

As the fluorine group-containing resin in the acid decomposable resin(B), resins having at least one of repeating units represented by thefollowing general formulae (FA) to (FG) can be enumerated.

In the foregoing general formulae, R₁₀₀ to R₁₀₃ each represents ahydrogen atom, a fluorine atom, an alkyl group, a cycloalkyl group, anaryl group, an aralkyl group, an alkenyl group, an acyl group, anacyloxy group, or an alkynyl group.

R₁₀₄ and R₁₀₆ each represents a hydrogen atom, a fluorine atom, or analkyl group; and at least one of R₁₀₄ and R₁₀₆ represents a fluorineatom or a fluoroalkyl group. It is preferable that both of R₁₀₄ and R₁₀₆represent a trifluoromethyl group.

R₁₀₅ represents a hydrogen atom, an alkyl group, an acyl group, analkoxycarbonyl group, or a group capable of being decomposed by theaction of an acid.

A₁ represents a single bond, a divalent connecting group (for example,an alkylene group, a cycloalkylene group, an alkenylene group, anarylene group, —OCO—, —COO—, and —CON(R₂₄)—), or a connecting groupcontaining the plural number of these groups. R₂₄ represents a hydrogenatom or an alkyl group.

R₁₀₇ and R₁₀₈ each represents a hydrogen atom, a halogen atom, an alkylgroup, an alkoxy group, an alkoxycarbonyl group, or a group capable ofbeing decomposed by the action of an acid.

R₁₀₉ represents a hydrogen atom, an alkyl group, or a group capable ofbeing decomposed by the action of an acid.

b is 0, 1 or 2.

Each of the repeating units represented by the general formulae (FA) to(FG) contains at least one fluorine atom, and preferably three or morefluorine atoms per repeating unit.

In the foregoing general formulae (FA) to (FG), examples of the alkylgroup include an alkyl group having from 1 to 8 carbon atoms, andspecifically, a methyl group, an ethyl group, a propyl group, an n-butylgroup, a sec-butyl group, a hexyl group, a 2-ethylhexyl group, and anoctyl group can be preferably enumerated.

The cycloalkyl group may be monocyclic or polycyclic. The monocyclictype is one having from 3 to 8 carbon atoms, and examples thereofinclude a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, acycloheptyl group, and a cyclooctyl group. The polycyclic type is onehaving from 6 to 20 carbon atoms, and examples thereof include anadamantly group, a norbornyl group, an isoboronyl group, a camphanylgroup, a dicyclopentyl group, an α-pinel group, a tricyclodecanyl group,a tetracyclodecyl group, and an androstanyl group. However, the carbonatom in the foregoing monocyclic or polycyclic cycloalkyl group may besubstituted with a hetero atom such as an oxygen atom.

Examples of the fluoroalkyl group include one having from 1 to 12 carbonatoms, and specifically, a trifluoromethyl group, a perfluoroethylgroup, a perfluoropropyl group, a perfluorobutyl group, a perfluorohexylgroup, a perfluorooctyl group, a perfluorooctylethyl group, and aperfluorododecyl group can be preferably enumerated.

Examples of the aryl group include an aryl group having from 6 to 15carbon atoms, and specifically, a phenyl group, a tolyl group, adimethylphenyl group, a 2,4,6-trimethyl phenyl group, a naphthyl group,an anthryl group, and a 9,10-dimethoxyanthryl group can be preferablyenumerated.

Examples of the aralkyl group include an aralkyl group having from 7 to12 carbon atoms, and specifically, a benzyl group, a phenethyl group,and a naphthylmethyl group can be preferably enumerated.

Examples of the alkenyl group include an alkenyl group having from 2 to8 carbon atoms, and specifically, a vinyl group, an allyl group, abutenyl group, and a cyclohexenyl group can be preferably enumerated.

Examples of the alkoxy group include an alkoxy group having from 1 to 8carbon atoms, and specifically, a methoxy group, an ethoxy group, ann-propoxy group, an isopropoxy group, a butoxy group, a pentoxy group,an allyoxy group, and an octoxy group can be preferably enumerated.

Examples of the acyl group include an acyl group having from 1 to 10carbon atoms, and specifically, a formyl group, an acetyl group, apropanoyl group, a butanoyl group, a pivaloyl group, an octanoyl group,and a benzoyl group can be preferably enumerated.

As the acyloxy group, an acyloxy group having from 2 to 12 carbon atomsis preferable, and examples thereof include an acetoxy group, apropionyloxy group, and a benzoyloxy group.

As the alkynyl group, an alkynyl group having from 2 to 5 carbon atomsis preferable, and examples thereof include an ethynyl group, a propynylgroup, and a butynyl group.

The alkoxycarbonyl group is preferably a secondary or tertiaryalkoxycarbonyl group, and more preferably a tertiary alkoxycarbonylgroup, such as an isopropoxycarbonyl group, a t-butoxycarbonyl group, at-amyloxycarbonyl group, and a 1-methyl-1-cyclohexyloxycarbonyl group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, abromine atom, and an iodine atom.

The alkylene group is preferably one having from 1 to 8 carbon atoms,such as a methylene group, an ethylene group, a propylene group, abutylene group, a hexylene group, and an octylene group, each of whichmay have a substituent.

The alkenylene group is preferably one having from 2 to 6 carbon atoms,such as an ethenylene group, a propenylene group, a butenylene group,each of which may have a substituent.

The cycloalkylene group is preferably one having from 5 to 8 carbonatoms, such as a cyclopentylene group and a cyclohexylene group, each ofwhich may have a substituent.

The arylene group is preferably one having from 6 to 15 carbon atoms,such as a phenylene group, a tolylene group, and a naphthylene group,each of which may have a substituent.

Also, these groups may have a substituent. Examples of the substituentinclude ones having active hydrogen such as an alkyl group, a cycloalkylgroup, an aryl group, an amino group, an amide group, a ureido group, aurethane group, a hydroxyl group, and a carboxyl group, a halogen atom(for example, a fluorine atom, a chlorine atom, a bromine atom, and aniodine atom), an alkoxy group (for example, a methoxy group, an ethoxygroup, a propoxy group, and a butoxy group), a thioether group, an acylgroup (for example, an acetyl group, a propanoyl group, and a benzoylgroup), an acyloxy group (for example, an acetoxy group, a propanoyloxygroup, and a benzoyloxy group), an alkoxycarbonyl group (for example, amethoxycarbonyl group, an ethoxycarbonyl group, and a propoxycarbonylgroup), a cyano group, and a nitro group.

Here, as the alkyl group, the cycloalkyl group, and the aryl group,those described previously are enumerated. The alkyl group may befurther substituted with a fluorine atom or a cycloalkyl group.

Examples of the group capable of being decomposed by the action of anacid, which is contained in the fluorine group-containing resin of theinvention, include —O—C—(R₃₆)(R₃₇)(R₃₈), —O—C(R₃₆)(R₃₇)(OR₃₉),—O—COO—C(R₃₆)(R₃₇)(R₃₈), —O—C(R₀₁)(R₀₂)COO—C(R₃₆)(R₃₇)(R₃₈),—COO—C(R₃₆)(R₃₇)(R₃₈), and —COO—C(R₃₆)(R₃₇)(OR₃₉).

R₃₆ to R₃₉ each represents an alkyl group, a cycloalkyl group, an arylgroup, an aralkyl group, or an alkenyl group; and R₀₁ and R₀₂ eachrepresents a hydrogen atom, an alkyl group, a cycloalkyl group, analkenyl group, an aralkyl group, or an aryl group.

Preferred specific examples thereof include an ether group or an estergroup of a tertiary alkyl group such as a t-butyl group, a t-amyl group,a 1-alkyl-1-cyclohexyl group, a 2-alkyl-2-adamantyl group, a2-adamantyl-2-propyl group, and a 2-(4-methylcyclohexyl)-2-propyl group,an acetal group or an acetal ester group such as a 1-alkoxy-1-ethoxygroup, and a tetrahydropyranyl group, a t-alkyl carbonate group, and at-alkylcarbonylmethoxy group.

Specific examples of the repeating structural units represented by thegeneral formulae (FA) to (FG) will be given below, but it should not beconstrued that the invention is limited thereto.

The total content of the repeating units represented by the generalformulae (FA) to (FG) is generally in the range of from 10 to 80% bymole, preferably from 30 to 70% by mole, and more preferably from 35 to65% by mole based on the whole of the repeating units constituting theresin.

In addition to the foregoing repeating structural units, the resin (B)of the invention may be copolymerized with other polymerizable monomerfor the purpose of further enhancing the performance of the resin of theinvention.

Examples of copolymerizable monomers that can be used include thosedescribed blow. That is, examples include compounds having one additionpolymerizable unsaturated bond, which are selected from acrylic esters,acrylamides, methacrylic esters, methacrylamides, allyl compounds, vinylethers, vinyl esters, styrenes, and crotonic esters other than thosedescribed above.

From the viewpoints of enhancing the dry etching resistance, adjustingthe alkali solubility, and enhancing the adhesion to a substrate, it ispreferable that such a fluorine group-containing resin contains otherrepeating unit as a copolymerization component in addition to theforegoing fluorine atom-containing repeating unit. Preferred examples ofother repeating unit include those described below.

1) A repeating unit having the alicyclic hydrocarbon structurerepresented by any one of the foregoing general formulae (pI) to (pVI)and (II-AB). Specifically, the repeating units of the foregoing 1 to 23and the repeating units of the foregoing [II-1] to [II-32]. Above all,the foregoing specific examples 1 to 23 in which R_(x) is CF₃ arepreferable.

2) A repeating unit having the lactone structure represented by any oneof the foregoing general (Lc) and (V-1) to (V-5). Specifically, therepeating units of the foregoing (IV-1) to (IV-16) and the repeatingunits of the foregoing (Ib-1) to (Ib-11).

3) A repeating unit represented by any one of the following generalformulae (XV), (XVI) and (XVII), which is derived from maleic anhydride,vinyl ether, or a cyano group-containing vinyl compound. Specifically,the repeating units of the foregoing (C-1) to (C-15). A fluorine atommay not be contained in these other repeating units.

In the formulae, R₄₁ represents an alkyl group, a cycloalkyl group, anaralkyl group, or an aryl group. The alkyl group of R₄, may besubstituted with an aryl group.

R₄₂ represents a hydrogen atom, a halogen atom, a cyano group, or analkyl group.

A₅ represents a single bond, a divalent alkyl group, alkenylene group,cycloalkylene group or arylene group, —O—CO—R₂₂—, —CO—O—R₂₃—, or—CO—N(R₂₄)—R₂₅—.

R₂₂, R₂₃, and R₂₅ may be the same or different and each represents asingle bond or a divalent alkylene group, alkenylene group,cycloalkylene group or arylene group, each of which may have an ethergroup, an ester group, an amide group, a urethane group, or a ureidogroup.

R₂₄ represents a hydrogen atom, an alkyl group, a cycloalkyl group, anaralkyl group, or an aryl group.

Here, as examples of the respective substituents, the same examples asin the substituents of the foregoing general formulae (FA) to (FG) areenumerated.

Also, specific examples of the repeating structural units represented bythe general formulae (XVI) to (XVII) will be given below, but it shouldnot be construed that the invention is limited thereto.

The content of other repeating units including the repeating unitsrepresented by the general formulae (XV) to (XVII) is generally in therange of from 0 to 70% by mole, preferably from 10 to 60% by mole, andmore preferably from 20 to 50% by mole based on the whole of therepeating structural units constituting the resin.

In the fluorine group-containing resin as the acid decomposable resin(B), the acid decomposable group may be contained in any repeating unit.

The content of the repeating unit having an acid decomposable group ispreferably from 10 to 70% by mole, more preferably from 20 to 60% bymole, and further preferably from 30 to 60% by mole based on the wholeof the repeating units.

The fluorine group-containing resin can be synthesized by radicalpolymerization likewise the alicyclic hydrocarbon based aciddecomposable resin.

The resin as the component (B) according to the invention preferably hasa weight average molecular weight, as reduced into polystyrene by theGPC method, of from 1,000 to 200,000. When the weight average molecularweight is 1,000 or more, it is possible to enhance the heat resistanceand dry etching resistance. Also, when the weight average molecularweight is not more than 200,000, not only it is possible to enhance thedevelopability, but also since the viscosity is extremely low, it ispossible to enhance the film forming property.

In the positive working composition of the invention, the compoundingamount of the resin as the component (B) according to the invention inthe whole of the composition is preferably from 40 to 99.99% by weight,and more preferably from 50 to 99.97% by weight in the whole of solids.

[3] (C) Dissolution inhibiting compound which is decomposed by theaction of an acid, whereby its solubility in an alkaline developerincreases, and which has a molecular weight of not more than 3,000(hereinafter sometimes referred to as “component (C)” or “dissolutioninhibiting compound”):

As the dissolution inhibiting compound (C) which is decomposed by theaction of an acid, whereby its solubility in an alkaline developerincreases, and which has a molecular weight of not more than 3,000, forthe purpose of not reducing the transmission at not longer than 220 nm,alicyclic or aliphatic compounds having an acid decomposable group, suchas acid decomposable group-containing cholic acid derivatives asdescribed in Proceeding of SPIE, 2724, 355 (1996). With respect to theacid decomposable group and alicyclic structure, those described in theforegoing alicyclic hydrocarbon based acid decomposable resin areenumerated.

In the case where the photosensitive composition of the invention isexposed with KrF excimer laser or irradiated with electron beams, onehaving a structure in which a phenolic hydroxyl group of a phenolcompound is substituted with an acid decomposable group is preferable.As the phenol compound, one having from 1 to 9 phenol skeletons ispreferable, and one having from 2 to 6 phenol skeletons is morepreferable.

In the invention, the dissolution inhibiting compound has a molecularweight of not more than 3,000, preferably from 300 to 3,000, and morepreferably from 500 to 2,500.

The amount of the dissolution inhibiting compound to be added ispreferably from 3 to 50% by weight, and more preferably from 5 to 40% byweight based on the solids of the photosensitive composition.

Specific examples of the dissolution inhibiting compound will be givenbelow, but it should not be construed that the invention is limitedthereto.

[4] (D) Resin soluble in an alkaline developer thereinafter sometimesreferred to as “component (D)” or “alkali-soluble resin”):

The alkali-soluble resin preferably has an alkali dissolution rate, asmeasured (at 23° C.) in 0.261N tetramethylammonium hydroxide (TMAH), of20 angstrom or more per second, and especially preferably 200 angstromor more per second.

Examples of the alkali-soluble resin to be used in the invention includenovolak resins, hydrogenated novolak resins, acetone-pyrogallol resins,o-polyhydroxystyrene, m-polyhydroxystyrene, p-polyhydroxystyrene,hydrogenated polyhydroxystyrene, halogen- or alkyl-substitutedpolyhydroxylstyrenes, hydroxystyrene-N-substituted maleimide copolymers,o/p- and m/p-hydroxystyrene copolymers, partially O-alkylated products(for example, O-methylated products of from 5 to 30% by mole,O-(1-methoxy)ethylated products, O-(1-ethoxy)ethylated products,O-2-tetra hydropyranylated products, and O-(t-butoxycarbonyl) methylatedproducts) or O-acylated products (for example, o-acetylated products offrom 5 to 30% by mole and O-(t-butoxy)carbonylated products) against thehydroxyl group of polyhydroxystyrene, styrene-maleic anhydridecopolymers, styrene-hydroxystyrene copolymers, α-methylstyrene-hydroxystyrene copolymers, carboxyl group-containing methacrylicresins and derivatives thereof, and polyvinyl alcohol derivatives.However, it should not be construed that the invention is limitedthereto.

Of these alkali-soluble resins, novolak resins, o-poly-hydroxystyrene,m-polyhydroxystyrene, p-polyhydroxystyrene and copolymers thereof;alkyl-substituted polyhydroxystyrenes; partially O-alkylated orO-acylated products of polyhydroxystyrene; styrene-hydroxystyrenecopolymers; and α-methylstyrene-hydroxystyrene copolymers are especiallypreferable.

The novolak resins can be obtained by subjecting a prescribed monomer asthe major component to addition condensation with an aldehyde in thepresence of an acid catalyst.

Also, the alkali-soluble resin has a weight average molecular weight of2,000 or more, preferably from 5,000 to 200,000, and more preferablyfrom 5,000 to 100,000.

The weight average molecular weight as referred to herein is defined asa value as reduced into polystyrene by the gel permeationchromatography.

In the invention, the alkali-soluble resin (D) may be used incombinations of two or more thereof.

The amount of the alkali-soluble resin to be used is from 40 to 97% byweight, and preferably from 60 to 90% by weight based on the solids ofthe whole of the composition of the photosensitive composition.

(5) (E) Acid crosslinking agent capable of crosslinking with theforegoing alkali-soluble resin by the action of an acid (hereinaftersometimes referred to as “component (E)” or “crosslinking agent”):

Though any compound can be used as the crosslinking agent so far as itcross-links the resin soluble in an alkaline developer by the action ofan acid, the following (1) to (3) are preferable.

-   (1) Hydroxymethyl body, alkoxymethyl body, or acyloxymethyl body of    phenol derivative.-   (2) Compound having an N-hydroxymethyl group, an N-alkoxymethyl    group, or an N-acyloxymethyl group.-   (3) Compound having an epoxy group.

The alkoxymethyl group is preferably one having not more than 6 carbonatoms; and the acyloxymethyl group is preferably one having not morethan 6 carbon atoms.

Of these crosslinking agents, the following compounds are especiallypreferable.

In the formulae, L₁ to L₈ may be the same or different and eachrepresents a hydrogen atom, a hydroxymethyl group, a methoxymethylgroup, an ethoxymethyl group, or an alkyl group having from 1 to 6carbon atoms.

The crosslinking agent is usually used in an addition amount of from 3to 70% by weight, and preferably from 5 to 50% by weight in the solidsof the photosensitive composition.

<Other Components>

[5] (F) Basic Compound:

For the purpose of reducing a change of the performance with time fromexposure to heating, it is preferable that the photosensitivecomposition of the invention contains (F) a basic compound.

Structures represented by the following formulae (A) to (E) can beenumerated as the preferred structure.

Here, R²⁵⁰, R²⁵¹, and R²⁵² each independently represents a hydrogenatom, an alkyl group having from 1 to 20 carbon atoms, a cycloalkylgroup having from 3 to 20 carbon atoms, or an aryl group having from 6to 20 carbon atoms; and R²⁵⁰ and R²⁵¹ may be taken together to form aring. These groups may have a substituent. As the substituted alkylgroup and cycloalkyl group, an aminoalkyl group having from 1 to 20carbon atoms or an aminocycloalkyl group having from 3 to 20 carbonatoms, and a hydroxyalkyl group having from 1 to 20 carbon atoms or ahydroxycycloalkyl group having from 3 to 20 carbon atoms are preferable.

Also, these alkyl chains may contain an oxygen atom, a sulfur atom, or anitrogen atom.

In the formulae, R²⁵³, R²⁵⁴, R²⁵⁵ and R²⁵⁶ each independently representsan alkyl group having from 1 to 20 carbon atoms or a cycloalkyl grouphaving from 3 to 20 carbon atoms.

Preferred examples of compounds include guanidine, aminopyrrolidine,pyrazole, pyrazoline, piperazine, aminomorpholine,aminoalkylmorpholines, and piperidine, each of which may have asubstituent. As more preferable compounds, compounds having an imidazolestructure, a diazabicyclo structure, an onium hydroxide structure, anonium carboxylate structure, a trialkylamine structure, an anilinestructure, or a pyridine structure, alkylamine derivatives having ahydroxyl group and/or an ether bond, and aniline derivatives having ahydroxyl group and/or an ether bond can be enumerated.

Examples of compounds having an imidazole structure include imidazole,2,4,5-triphenylimidazole, and benzimidazole. Examples of compoundshaving a diazabicyclo structure include 1,4-diazabicyclo[2,2,2]octane,1,5-diazabicyclo[4,3,0]nona-5-ene, and 1,8-diazabicyclo [5,4,0]undeca-7-ene. Examples of compounds having an onium hydroxide structureinclude triarylsulfonium hydroxides, phenacylsulfonium hydroxides, andsulfonium hydroxides having a 2-oxoalkyl group, specifically,triphenylsulfonium hydroxide, tris(t-butylphenyl)sulfonium hydroxide,bis(t-butylphenyl) iodonium hydroxide, phenacylthiophenium hydroxide,and 2-oxopropylthiophenium hydroxide. Examples of compounds having anonium carboxylate structure include compounds having an onium hydroxidestructure in which an anion moiety thereof is a carboxylate, forexample, acetates, adamantane-1-carboxylates, and perfluoroalkylcarboxylates. Examples of compounds having a trialkylamine structureinclude tri (n-butyl) amine and tri (n-octyl) amine. Examples of anilinecompounds include 2,6-diisopropylaniline and N,N-dimethylaniline.Examples of alkylamine derivatives having a hydroxyl group and/or anether bond include ethanolamine, diethanolamine, triethanolamine, andtris (methoxyethoxyethyl)amine. Examples of aniline derivatives having ahydroxyl group and/or an ether bond includeN,N-bis(hydroxyethyl)aniline.

These basic compounds are used singly or in admixture of two or morethereof. The amount of the basic compound to be used is usually from0.001 to 10% by weight, and preferably from 0.01 to 5% by weight basedon the solids of the photosensitive composition. For the sake ofobtaining sufficient addition effects, it is preferable that the amountof the basic compound to be used is 0.001% by weight or more. On theother hand, in view of the sensitivity and the developability in anon-exposed area, it is preferable that the amount of the basic compoundto be used is not more than 10% by weight.

[6] (G) Fluorine based and/or silicon based surfactant:

It is preferable that the photosensitive composition of the inventioncontaining either one of a fluorine based surfactant and a silicon basedsurfactant (for example, a fluorine based surfactant and a silicon basedsurfactant, and a surfactant containing both of a fluorine atom and asilicon atom), or two or more thereof.

When the photosensitive composition of the invention contains a fluorineand/or silicon based surfactant, it is possible to give a resist patternhaving good sensitivity and resolution and having little adhesion anddevelopment defect at the time of using a light source of exposure ofnot longer than 250 nm, especially not longer than 220 nm.

Examples of such fluorine and/or silicon based surfactants includesurfactants described in JP-A-62-36663, JP-A-61-226746, JP-A-61-226745,JP-A-62-170950, JP-A-63-34540, JP-A-7-230165, JP-A-8-62834,JP-A-9-54432, JP-A-9-5988, JP-A-2002-277862, U.S. Pat. Nos. 5,405,720,5,360,692, 5,529,881, 5,296,330, 5,436,098, 5,576,143, 5,294,511, and5,824,451. Also, commercially available surfactants described below canbe used as they are.

Examples of commercially available surfactants that can be used includefluorine based surfactants or silicon based surfactants such as EftopSeries EF301 and EF303 (manufactured by Shin-Akita Kasei K. K.), FluoradSeries FC430 and FC431 (manufactured by Sumitomo 3M Ltd.), MegafoamSeries F171, F173, F176, F189, and R₀₈ (manufactured by Dainippon Inkand Chemicals, Incorporated), Sarfron Series S-382, SC101, SC102, SC103,SC104, SC105, and SC106 (manufactured by Asahi Glass Co., Ltd.), andTroysol S-366 (manufactured by Troy Chemical Industries, Inc.). Also, apolysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co.,Ltd.) can be used as the silicon based surfactant.

Also, in addition to the foregoing known surfactants, surfactants usinga polymer having a fluoro aliphatic group derived from a fluoroaliphatic compound produced by the telomerization method (also called“telomere method”) or the oligomerization method (also called “oligomermethod”) can be used as the surfactant. The fluoro aliphatic compoundcan be synthesized by a method described in JP-A-2002-90991.

As the fluoro aliphatic group-containing polymer, copolymers of a fluoroaliphatic group-containing monomer and a (poly(oxyalkylene)) acrylateand/or a (poly(oxyalkylene)) methacrylate are preferable, and thesecopolymers may be one in which the monomers are irregularly distributedor block copolymerized. Also, examples of the poly(oxyalkylene) groupinclude a poly(oxyethylene) group, a poly(oxypropylene) group, and apoly(oxybutylene) group. Also, units having alkylene groups having adifferent chain length in the same chain length, such as apoly(oxyethylene/oxypropylene/oxyethylene block linking body) and apoly(oxyethylene/oxypropylene block linking body), may be employed.Further, the copolymer of a fluoro aliphatic group-containing monomerand a (poly (oxyalkylene)) acrylate (or methacrylate) includes not onlybinary copolymers but also ternary or more copolymers in which two ormore of different fluoro aliphatic group-containing monomers and two ormore of different (poly (oxyalkylene)) acrylates (or methacrylates) arecopolymerized simultaneously.

For example, Megaface Series F178, F-470, F-473, F-475, F-476, and F-472(manufactured by Dainippon Ink and Chemicals, Incorporated) can beenumerated as a commercially available surfactant. Further, copolymersof a C₆F₁₃ group-containing acrylate (or methacrylate) and a (poly(oxyalkylene)) acrylate (or methacrylate), copolymers of a C₆F₁₃group-containing acrylate (or methacrylate), a (poly (oxyethylene))acrylate (or methacrylate) and a (poly (oxypropylene)) acrylate (ormethacrylate), copolymers of a C₈F₁₇ group-containing acrylate (ormethacrylate) and a (poly (oxyalkylene)) acrylate (or methacrylate), andcopolymers of a C₈F₁₇ group-containing acrylate (or methacrylate), a(poly (oxyethylene)) acrylate (or methacrylate) and a (poly(oxypropylene)) acrylate (or methacrylate) can be enumerated.

The amount of the fluorine and/or silicon based surfactant to be used ispreferably from 0.0001 to 2% by weight, and more preferably from 0.001to 1% by weight based on the total amount (exclusive of the solvent) ofthe photosensitive composition.

[7] (H) Organic Solvent:

The photosensitive composition of the invention is used upon dissolvingthe foregoing components in a prescribed organic solvent.

Examples of the organic solvent that can be used include ethylenedichloride, cyclohexanone, cyclopentanone, 2-heptanone, γ-butyrolactone,methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycolmonoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl etheracetate, propylene glycol monomethyl ether, propylene glycol monomethylether acetate, toluene, ethyl acetate, methyl lactate, ethyl lactate,methyl methoxypropionate, ethyl ethoxypropionate, methylpyruvate, ethylpyruvate, propyl pyruvate, N,N-dimethylformamide, dimethyl sulfoxide,N-methylpyrrolidone, and tetrahydrofuran.

In the invention, though the organic solvent may be used singly or inadmixture, it is preferred to use a mixed solvent of a solventcontaining a hydroxyl group in the structure and a solvent notcontaining a hydroxyl group in the structure. In this way, it ispossible to reduce the generation of particles at the time of storage ofthe resist.

Examples of the solvent containing a hydroxyl group include ethyleneglycol, ethylene glycol monomethyl ether, ethylene glycol monoethylether, propylene glycol, propylene glycol monomethyl ether, propyleneglycol monoethyl ether, and ethyl lactate. Of these, propylene glycolmonomethyl ether and ethyl lactate are especially preferable.

Examples of the solvent not containing a hydroxyl group includepropylene glycol monomethyl ether acetate, ethyl ethoxypropionate,2-heptanone, γ-butyrolactone, cyclohexanone, cyclohexanone, butylacetate, N-methylpyrrolidone, N,N-dimethylacetamide, and dimethylsulfoxide. Of these, propylene glycol monomethyl ether acetate, ethylethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butylacetate are especially preferable; and propylene glycol monomethyl etheracetate, ethyl ethoxypropionate, and 2-heptanone are the mostpreferable.

A mixing ratio (by weight) of the solvent containing a hydroxyl group tothe solvent not containing a hydroxyl group is from 1/99 to 99/1,preferably from 10/90 to 90/10, and more preferably from 20/80 to 60/40.A mixed solvent containing 50% by weight or more of the solvent notcontaining a hydroxyl group is especially preferable in view of coatinguniformity.

(Ha) Solvent containing at least one cyclic ketone:

In the case where the positive photosensitive composition contains thealicyclic hydrocarbon based acid decomposable resin, it is preferred touse a solvent containing at least one cyclic ketone as the organicsolvent.

By using the alicyclic hydrocarbon based acid decomposable resin and thecyclic ketone, the positive photosensitive composition of the inventionhardly causes pattern collapse and can widen the defocus latitude withrespect to the isolated line pattern.

Examples of the cyclic ketone include compounds having from 5 to 8carbon atoms in total, such as cyclopentanone,3-methyl-2-cyclopentanone, cyclohexanone, 2-methylcyclohexanone,2,6-dimethylcyclohexanone, cycloheptanone, cyclooctanone, andisophorone. Of these, cyclohexanone and cycloheptanone are preferable.

The cyclic ketone can be used singly or as a mixed solvent with othersolvent. Examples of the solvent to be mixed (associative solvent)include propylene glycol monoalkyl ether carboxylates, alkyl lactates,propylene glycol monoalkyl ethers, alkyl alkoxypriopionates, and linearketones.

Specific examples of propylene glycol monoalkyl ether carboxylatesinclude propylene glycol monomethyl ether acetate, propylene glycolmonomethyl ether propionate, and propylene glycol monoethyl etheracetate.

Examples of alkyl lactates include methyl lactate and ethyl lactate.

Examples of propylene glycol monoalkyl ethers include propylene glycolmonomethyl ether and propylene glycol monoethyl ether.

Examples of alkyl alkoxypropionates include methyl methoxypropionate,ethyl methoxypropionate, methyl ethoxypropionate, and ethylethoxypropionate.

Examples of linear ketones include methyl ethyl ketone, 2-heptanone,3-heptanone, and 4-heptanone.

Preferred examples of the associative solvent include propylene glycolmonoalkyl ether carboxylates, alkyl lactates, and propylene glycolmonoalkyl ethers.

By combining the cyclic ketone with the associative solvent, theadhesion to a substrate, developability, DOF, and the like are improved.

A ratio (weight ratio) of the cyclic ketone to the associative solventis preferably from 30/70 to 95/5, more preferably from 35/65 to 90/10,and further preferably from 40/60 to 80/20.

Also, from the viewpoint of enhancing the uniformity of film thicknessand the development defect performance, it is preferred to mix ahigh-boiling solvent having a boiling point of 200° C. or higher, suchas ethylene carbonate, propylene carbonate, and γ-butyrolactone.

The addition amount of the high-boiling solvent is from 0.1 to 15% byweight, preferably from 0.5 to 10% by weight, and further preferablyfrom 1 to 5% by weight in the whole of solvents.

By using such a cyclic ketone singly or a mixed solvent with othersolvent, the photosensitive composition having a concentration of solidsof generally from 3 to 25% by weight, preferably from 5 to 22% byweight, and more preferably from 7 to 20% by weight is prepared.

<Other Additives>

If desired, the photosensitive composition of the invention may furthercontain a dye, a plasticizer, a surfactant other than the foregoingcomponent (G), a photosensitizer, a compound capable of accelerating thedissolution in a developer, and the like.

A dissolution accelerating compound in a developer, which can be used inthe invention, is a low-molecular compound having two or more OHphenolic groups or one or more carboxy groups and having a molecularweight of not more than 1,000. In the case where the dissolutionaccelerating compound has a carboxy group(s), alicyclic or aliphaticcompounds are preferable.

The addition amount of the dissolution accelerating compound ispreferably from 2 to 50% by weight, and more preferably from 5 to 30% byweight based on the resin as the component (B) or the resin as thecomponent (D). In view of inhibition of development residues andprevention of pattern deformation at the time of development, it ispreferable that the addition amount of the dissolution acceleratingcompound is not more than 50% by weight.

Such a phenolic compound having a molecular weight of not more than1,000 can be easily synthesized by those skilled in the art by referringto methods described in, for example, JP-A-4-122938, JP-A-2-28531, U.S.Pat. No. 4,916,210, and European Patent No. 219,294.

Specific examples of the carboxyl group-containing alicyclic oraliphatic compound include carboxylic acid derivatives having a steroidstructure (for example, cholic acid, deoxycholic acid, and lithocholicacid), adamantanecarboxylic acid derivatives, adamantanedicarboxylicacids, cyclohexanecarboxylic acid, and cyclohexanedicarboxylic acids.However, it should not be construed that the invention is limitedthereto.

In the invention, surfactants other than the foregoing fluorine basedand/or silicon based surfactant (G) can be added. Specific examplesthereof include nonionic surfactants such as polyoxyethylene alkylethers, polyoxyethylene alkylaryl ethers,polyoxyethylene/polyoxypropylene block copolymers, sorbitan aliphaticesters, and polyoxyethylene sorbitan aliphatic esters.

These surfactants can be added singly or in combinations.

<<Use Method>>

The photosensitive composition of the invention is used by dissolvingthe respective components in a prescribed solvent, preferably theforegoing mixed solvent and coating the solution on a prescribed supportin the following manner.

For example, the photosensitive composition is coated on a substrate tobe used in the manufacture of precision integrated circuit devices (forexample, a silicon/silicon dioxide coating) by an adequate coatingmethod using a spinner, a coater, etc., and then dried to form aphotosensitive film.

The photosensitive film is irradiated with the actinic ray or theradiation through a prescribed mask, baked (heated), and then developed.In this way, a good pattern can be obtained.

Though as the the actinic ray or the radiation, infrared light, visiblelight, ultraviolet light, far ultraviolet light, X-rays, and electronbeams can be enumerated, far ultraviolet light preferably having awavelength of not longer than 250 nm, and more preferably not longerthan 220 nm, specifically, a KrF excimer laser (248 nm), an ArF excimerlaser (193 nm), an F₂ excimer laser (157 nm), X-rays, and electron beamsare preferable, and an ArF excimer laser and an F₂ excimer laser, andEUV (13 nm) are more preferable.

In the development step, an alkaline developer is used in the followingmanner. As the alkaline developer of the resist composition, alkalineaqueous solutions of, for example, inorganic alkalis such as sodiumhydroxide, potassium hydroxide, sodium carbonate, sodium silicate,sodium metasilicate, and ammonia water, primary amines such asethylamine and n-propylamine, secondary amines such as diethylamine anddi-n-butylamine, tertiary amines such as triethylamine andmethyldiethylamine, alcohol amines such as dimethylethanolamine andtriethanolamine, quaternary ammonium salts such as tetramethylammoniumhydroxide and tetraethylammonium hydroxide, and cyclic amines such aspyrrole and piperidine, can be used.

Further, suitable amounts of alcohols or surfactants can be added to andused in the foregoing alkaline developer.

The alkaline developer generally has an alkali concentration of from 0.1to 20% by weight.

The alkaline developer generally has a pH of from 10.0 to 15.0.

EXAMPLES

The invention will be described below in more detail with reference tothe following Examples, but it should not be construed that the contentsof the invention are limited thereto.

<Compound (A)>

Synthesis Example 1 Synthesis of Compound (I-1)

8.44 g (18.6 mmoles) of diiodoperfluorobutane, 8.50 g (48.8 mmoles) ofsodium hydrosulfite, 4.60 g (55 mmoles) of sodium hydrogencarbonate, 25mL of acetonitrile, and 15 mL of water were added, and the mixture wasstirred at room temperature for one hour. The reaction solution wasfiltered, and a filtrate was ice cooled to deposit a white solid. Thissolid was collected by filtration and dried to obtain 6.8 g (98%) ofsodium perfluorobutane-1,5-disulfinate.

15.77 g (40.4 mmoles) of triphenylsulfonium iodide, 7.07 g (42.4 mmoles)of silver acetate, 400 mL of acetonitrile, and 200 mL of water wereadded, and the mixture was stirred at room temperature for one hour. Thereaction solution was filtered to obtain a triphenylsulfonium acetatesolution.

7.2 g (19.2 mmoles) of sodium perfluorobutane-1,5-disulfinate, 80 mL ofaqueous hydrogen peroxide (30%), and 8 mL of acetic acid were added, andthe mixture was stirred at 60° C. for 4 hours. After confirming thecompletion of the reaction by ¹⁹F-NMR, the reaction solution wasneutralized by the addition of 30 mL of 1N-NaOH, to which was then addedthe foregoing triphenylsulfonium acetate solution, and the mixture wasstirred at room temperature for three hours. 500 mL of chloroform wasadded, and an organic layer was washed successively with water, anaqueous saturated sodium sulfite solution, water, an aqueous saturatedammonium chloride solution, and water. The organic layer was filteredusing a 0.1 μm filter, and the solvent was removed using an evaporatorto obtain a colorless transparent oil. This oil was crystallized byallowing to stand at −10° C. for 6 hours, and crystals were collected byfiltration and dried to obtain a desired compound (I-1) (7.5 g, 44%).

¹H-NMR (300 MHz, CDCl₃): δ7.27 to 7.55 (m, 9H), 7.70 to 7.69 (m, 6H)

¹⁹F-NMR (300 MHz, CDCl₃): δ−114 (t, 4F), −120 (t, 4F) Other acidgenerating agents were synthesized in the same manner.

<Resin (B)>

Synthesis Example 1 Synthesis of Resin (1) (Side Chain Type)

2-Ethyl-2-adamantyl methacrylate and butyrolactone methacrylate werecharged in a proportion of 55/45 and dissolved in methyl ethylketone/tetrahydrofuran (5/5) to prepare 100 mL of a solution having aconcentration of solids of 20%. To this solution, 2% by mole of V-65,manufactured by Wako Pure Chemical Industries, Ltd. was added, and themixture was dropped in 10 mL of methyl ethyl ketone heated at 60° C.over 4 hours in a nitrogen atmosphere. After completion of dropping, thereaction solution was heated for 4 hours, 1% by mole of V-65 was againadded, and the mixture was stirred for 4 hours. After completion of thereaction, the reaction solution was cooled to room temperature andcrystallized from 3 L of a mixed solvent of distilled water/isopropylalcohol (1/1), thereby recovering a resin (1) as a deposited whitepowder.

The polymer formulation ratio determined by C¹³-NMR was 46/54. Also, theweight average molecular weight as reduced into standard polystyrene bythe GPC measurement was 10,700.

Resins (2) to (12) and (26) to (31) were synthesized in the same manneras in the foregoing Synthesis Example 1.

Synthesis Example 2 Synthesis of Resin (13) (Principal Chain Type)

t-Butyl norbornenecarboxylate, butyrolactone norbornenecarboxylate andmaleic anhydride (molar ratio: 40/10/50) and THF (reactionconcentration: 60% by weight) were charged in a separable flask, and themixture was heated at 60° C. under a nitrogen gas stream. When thereaction temperature became stable, 2% by mole of a radical initiatorV-601, manufactured by Wako Pure Chemical Industries, Ltd. was added toinitiate reaction. The mixture was heated for 12 hours. The resultingreaction mixture was diluted two times with tetrahydrofuran and thenthrown into a mixed solution of hexane/isopropyl alcohol (1/1) todeposit a white powder. The deposited powder was taken out by filtrationand dried to obtain a desired resin (13).

The resulting resin (13) was subjected to molecular weight analysis byGPC and found to be 8,300 (weight average) as reduced into polystyrene.Also, according to the NMR spectrum, the resin (13) was confirmed tohave a molar ratio of t-butyl norbornenecarboxyllate/butyrolactonenorbornenecarboxylate/maleic anhydride repeating units of 42/8/50.

Resins (14) to (19) were synthesized in the same manner as in SynthesisExample 2.

Synthesis Example 3 Synthesis of Resin (20) (Hybrid Type)

Norbornene, maleic anhydride, t-butyl acrylate, and2-methylcyclohexyl-2-propyl acrylate were charged in a molar ratio of35/35/20/10 in a reactor, and the mixture was dissolved intetrahydrofuran to prepare a solution having a content of solids of 60%.This solution was heated at 65° C. under a nitrogen gas stream. When thereaction temperature became stable, 1% by mole of a radical initiatorV-601, manufactured by Wako Pure Chemical Industries, Ltd. was added toinitiate reaction. After heating for 8 hours, the reaction mixture wasdiluted two times with tetrahydrofuran, and the reaction mixed solutionwas thrown into a five-time volume of hexane to deposit a white powder.The deposited powder was taken out by filtration, dissolved in methylethyl ketone, and re-precipitated in a five-time volume of ahexane/t-butyl methyl ether (1/1) solution. A deposited white powder wascollected by filtration and dried to obtain a desired resin (20).

The resulting resin (20) was subjected to molecular weight analysis byGPC and found to be 12, 100 (weight average) as reduced intopolystyrene. Also, according to the NMR spectrum, the resin (20) had aformulation having a molar ratio of norbornene/maleic anhydride/t-butylacrylate/2-methyl cyclohexyl-2-propyl acrylate of 32/39/19/10.

Resins (21) to (25) were synthesized in the same manner as in SynthesisExample 3.

Structures and molecular weights of the resins (1) to (31) will be givenbelow.

Molecular weight (1)

10700

(2)

9400

(3)

8300

(4)

10300

(5)

8900

(6)

11300

(7)

8900

(8)

11700

(9)

9800

(10)

8700

(11)

13400

(12)

10900

(13)

8300

(14)

8200

(15)

9600

(16)

5800

(17)

4700

(18)

8500

(19)

8900

(20)

12100

(21)

13900

(22)

12400

(23)

12700

(24)

10800

(25)

9300

(26)

9300

(27)

7600

(28)

7300

(29)

7600

(30)

8400

(31)

6500

Synthesis Example 4 Synthesis of Resin (RA21)

A mixture of t-butyl norbornenecarboxylate, norbornenecarboxylic acid,2-hydroxyethyl norbornenecarboxylate, and maleic anhydride was dissolvedin tetrahydrofuran to prepare a solution having a content of solids of50% by weight. This solution was charged into a three-necked flask andheated at 60° C. under a nitrogen gas stream. When the reactiontemperature became stable, 5% by mole of a radical initiator V-60,manufactured by Wako Pure Chemical Industries, Ltd. was added toinitiate reaction. After heating for 6 hours, the reaction mixture wasdiluted two times with tetrahydrofuran, and the reaction solution wasthrown into a five-time volume of hexane to deposit a white powder. Thepowder was again dissolved in tetrahydrofuran, and the solution wasthrown into a five-time volume of hexane to deposit a white powder. Thedeposited powder was taken out by filtration and dried to obtain adesired resin (RA21) having the following repeating unit (formula (1) ofJP-A-2000-241964).

The resulting resin (RA21) was subjected to molecular weight analysis(RI analysis) by GPC and found to be 7,900 (weight average) as reducedinto polystyrene.

The following resins (RA1) to (RA20) were obtained in the same manner.

Synthesis Example 5 Synthesis of Resin (RB1)

2-Methyl-2-adamantyl methacrylate, β-hydroxy-γ-butyro lactonemethacrylate, and 3-hydroxy-1-adamantyl methacrylate were charged in aproportion of 50/25/25, and the mixture was dissolved in propyleneglycol monomethyl ether acetate/propylene glycol monomethyl ether(70/30) (weight ratio) to prepare 450 g of a solution having aconcentration of solids of 22% by weight. 1.5% by mole of apolymerization initiator V-601, manufactured by Wako Pure ChemicalIndustries, Ltd. was added to this solution, and the mixture was droppedin 50 g of a mixed solution of propylene glycol monomethyl etheracetate/propylene glycol monomethyl ether (70/30) (weight ratio) heatedat 100° C. over 6 hours in a nitrogen atmosphere. After completion ofdropping, the reaction solution was stirred for 2 hours. Aftercompletion of the reaction, the reaction solution was cooled to roomtemperature and crystallized from 5 L of a mixed solvent of hexane/ethylacetate (9/1) (weight ratio). A deposited white powder was collected byfiltration to recover a desired resin (RB1).

The polymer formulation ratio (2-methyl-2-adamantylmethacrylate/β-hydroxy-γ-butyrolactonemethacrylate/3-hydroxy-1-adamantyl methacrylate) determined by the¹³C-NMR and the weight average molecular weight and degree of dispersion(Mw/Mn) as reduced into standard polystyrene by the GPC measurement wereas follows.

Alicyclic hydrocarbon based acid decomposable resins (RB2) to (RB14)were synthesized in the same manner.

Structures, weight average molecular weights, and degrees of dispersionof the alicyclic hydrocarbon based acid decomposable resins (RB1) to(RB14) will be given below.

Also, Resin A4 of Synthesis Example 10 of JP-A-10-274852, Resin H ofSynthesis Example 8 of JP-A-2000-137327, and Resin (1) of SynthesisExample (1) of JP-A-2001-109154 were synthesized and designated asresins R1, R2 and R3, respectively.

Structures of repeating units of these reins will be given below. Theweight average molecular weight was 8,000 for R1, 14,000 for R2, and7,200 for R3, respectively.

<Fluorine Group-containing Resin>

Structures of fluorine group-containing resins (FII-1) to (FII-40) to beused in the Examples will be given below.

Also, the following Tables 1 and 2 show weight average molecular weightsof the fluorine group-containing resins (FII-1) to (FII-40).

TABLE 1

Weight average Content of oligomer having a molecular weight Degree ofmolecular weight of not more Resin Mw dispersion than 1,000 (FII-1) 15200 1.45 5 (FII-2)  24000 1.75 8 (FII-3)  18200 1.85 7 (FII-4)  165001.46 6 (FII-5)   9500 1.58 8 (FII-6)  19500 2.02 8 (FII-7)   6500 1.85 7(FII-8)  28400 1.68 9 (FII-9)  28600 1.44 5 (FII-10) 12800 1.65 8(FII-11) 16800 1.68 9 (FII-12) 28400 1.58 6 (FII-13) 19800 1.69 8(FII-14)  8700 1.95 8 (FII-15) 15200 1.46 7 (FII-16) 19500 1.65 4(FII-17) 16900 1.42 8 (FII-18) 15900 1.85 9 (FII-19) 15000 1.55 4(FII-20) 12500 1.88 8 (FII-21) 25000 1.68 9 (FII-22) 16000 1.54 7(FII-23) 14600 1.95 5 (FII-24) 17500 1.48 5 (FII-25) 16500 1.52 6(FII-26) 14600 1.63 5

TABLE 2 Weight average molecular weight Degree of Resin Mw dispersion(FII-27) 8300 1.55 (FII-28) 8300 1.62 (FII-29) 8000 1.52 (FII-30) 92001.71 (FII-31) 10200 1.47 (FII-32) 7900 1.35 (FII-33) 6800 1.60 (FII-34)7400 1.59 (FII-35) 8300 1.70 (FII-36) 4800 1.55 (FII-37) 4700 1.51(FII-38) 6400 1.69 (FII-39) 9600 1.70 (FII-40) 4600 1.68

Examples 1 to 25 and Comparative Examples 1 and 2

<Preparation of Resist>

Components shown in the following Tables 3 to 5 were dissolved in asolvent to prepare solutions each having a concentration of solids of12% by weight. Each solution was filtered by a 0.1 μmpolytetrafluoroethylene filter or polyethylene filter to prepare apositive working resin solution. The prepared positive resist solutionswere evaluated according to the following methods. The results are shownin Tables 3 to 5.

Abbreviations in Tables 3 to 8 and Tables 10 to 13 are as follows.Resins and acid generating agents other than those described below arethose enumerated previously. Also, in the respective tables, in the casewhere the plural number of resins or solvents are used, the given ratiosare a weight ratio.

[Acid Generating Agent]

The compound (A) of the invention and the associative acid generatingagent are those enumerated previously.

However, PGA-A is a compound described below.

[Basic Compound]

-   DBN: 1,5-Diazabicyclo[4,3,0]nona-5-ene-   TPI: 2,4,5-Triphenylimidazole-   TPSA: Triphenylsulfonium acetate-   HEP: N-Hydroxyethylpiperidine-   DIA: 2,6-Diisopropylaniline-   DCMA: Dicyclohexylmethylamine-   TPA: Tripentylamine-   TOA: Tri-n-octylamine-   HAP: Hydroxyantipyrine-   TBAH: Tetrabutylammonium hydroxide-   TMEA: Tris(methoxyethoxyethyl)amine-   PEA: N-Phenyldiethanolamine

[Surfactant]

-   W-1: Megaface F176 (manufactured by Dainippon Ink and Chemicals,    Incorporated) (fluorine based)-   W-2: Megaface R₀₈ (manufactured by Dainippon Ink and Chemicals,    Incorporated) (fluorine and silicon based)-   W-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical    Co., Ltd.) (silicon based)-   W-4: Troysol S-366 (manufactured by Troy Chemical Industries, Inc.)

[Solvent]

-   A1: Propylene glycol methyl ether acetate-   A2: 2-Heptanone-   A3: Ethyl ethoxypropionate-   A4: γ-Butyrolactone-   A5: Cyclohexanone-   B1: Propylene glycol methyl ether-   B2: Ethyl lactate

[Dissolution Inhibitor]

-   LCB: t-Butyl lithocholate    <Evaluation of Resist>

An anti-refractive film DUV-42, manufactured by Brewer Science Limitedwas uniformly coated in a thickness of 600 angstrom on ahexamethyldisilazane-treated silicon substrate using a spin coater,dried on a hot plate at 100° C. for 90 seconds, and then dried byheating at 190° C. for 240 seconds. Thereafter, each of the positiveworking resist solutions was coated using a spin coater and dried at120° C. for 90 seconds to form a 0.30 μm-thick resist film.

This resist film was exposed with an ArF excimer laser stepper(manufactured by ISI, NA=0.6) through a mask, and immediately after theexposure, heated on a hot plate at 120° C. for 90 seconds. Further, theresulting resist film was developed with a 2.38% by weighttetramethylammonium hydroxide aqueous solution at 23° C. for 60 seconds,rinsed with pure water for 30 seconds, and then dried to obtain a linepattern.

(Density Dependency)

In a line-and-space pattern with a line width of 0.13 μm (dense pattern:line-and-space=1/1) and an isolated line pattern (coarse pattern:line-and-space=1/5), an overlapping range of the depth of focus allowing(0.13 μm±10%) therebetween was determined. The larger the value, thesmaller the performance difference between the dense pattern and thecoarse pattern is, i.e., the density dependency is good.

(Exposure Latitude)

The exposure amount of reproducing a mask pattern of line-and-space witha line width of 0.13 μm was defined as an optimum exposure amount. Whenthe exposure amount was changed, a width of the exposure amount allowing(0.13 μm±10%) of the pattern size was determined. This value was dividedby the optimum exposure amount and expressed in terms of percentage. Thelarger the value, the smaller the performance change by the change ofthe exposure amount is, i.e., the exposure latitude is good.

TABLE 3 Formulation Associative Evaluation Acid acid Basic SolventDensity Exposure generating generating compound Surfactant (weightComponent dependency latitude agent (g) agent (g) Resin (g) (0.03 g)ratio) (C) (g) (μm) (%) Example 1 I-1 (0.3) — (1) 10 g DBN (002) W-1A1/B1 — 0.35 13.3 (60/40) Example 2 I-2 (0.5) — (2) 10 g TMEA (0.02) W-1A1/B1 — 0.35 13.7 (60/40) Example 3 I-3 (0.4) — (3) 10 g TPSA (0.02) W-2A1/B1 — 0.35 13.1 (60/40) Example 4 I-4 (0.2) z38 (0.15) (4) 10 g HEP(0.01) W-2 A3/B1 — 0.40 14.4 z50 (0.2) (80/20) Example 5 I-5 (0.5) z27(0.2) (5) 10 g TOA (0.03) W-3 A2/B1 — 0.40 14.2 (90/10) Example 6 I-6(0.4) z35 (0.2) (6) 10 g TBAH (0.01) W-3 A4/B1 LCB (1) 0.40 14.7 (90/10)Example 7 I-1 (0.4) — (7) 10 g TPA (0.007) W-4 A1/B1 — 0.40 14.1 (50/50)Example 8 I-10 (0.4) z18 (0.15) (8) 10 g DBN (0.02) W-4 A1/B1 — 0.4014.9 z49 (0.2) (90/10) Example 9 I-7 (0.5) z34 (0.1) (9) 10 g TPI (0.03)W-1 A5/B2 — 0.40 14.3 z52 (0.2) (90/10) Example 10 I-8 (0.4) z3 (0.2)(10) 5 g TPI (0.02) W-1 A1/B1 — 0.35 13.4 (13) 5 g (95/5)

TABLE 4 Formulation Associative Evaluation Acid acid Basic SolventDensity Exposure generating generating compound Surfactant (weightComponent dependency latitude agent (g) agent (g) Resin (g) (0.03 g)ratio) (C) (g) (μm) (%) Example 11 I-11 (0.6) z18 (0.1) (11) 5 g DIA(0.02) W-2 A1/B1 — 0.40 14.5 z32 (0.2) (14) 5 g (90/10) Example 12 I-13(0.6) z38 (0.15) (12) 6 g DIA (0.01) W-2 A1/B1 — 0.40 14.6 (15) 4 g HAP(0.01) (95/5) Example 13 I-12 (0.2) z14 (0.15) (16) 10 g TPI (0.03) W-3A1/B1 — 0.325 12.7 z51 (0.2) (95/5) Example 14 I-16 (0.5) z38 (0.2) (17)10 g DBN (0.02) W-3 A1/B1 — 0.30 11.2 z54 (0.1) (95/5) Example 15 I-18(0.2) z2 (0.1) (18) 3 g DIA (0.02) W-4 A1/B1 — 0.40 14.6 z31 (0.1) (31)7 g (80/20) Example 16 I-14 (0.2) z6 (0.1) (19) 10 g TPA (0.01) W-4A1/B1 — 0.30 11.6 z22 (0.1) (60/40) Example 17 I-15 (0.6) — (20) 10 gTPA (0.03) W-4 A1/B1 — 0.30 11.3 (60/40) Example 18 I-17 (0.2) z44 (0.4)(21) 10 g DCMA (0.01) W-4 A1/B1 — 0.325 12.7 (60/40) Example 19 I-20(0.2) z38 (0.15) (22) 10 g TPI (0.02) W-4 A1/B1 — 0.325 12.1 z40 (0.2)(95/5) Example 20 I-23 (0.1) z40 (0.3) (26) 5 g TPI (0.03) W-4 A1/B1 —0.35 13.5 z42 (0.1) (23) 5 g (95/5)

TABLE 5 Formulation Associative Evaluation Acid acid Basic SolventDensity Exposure generating generating compound Surfactant (weightComponent dependency latitude agent (g) agent (g) Resin (g) (0.03 g)ratio) (C) (g) (μm) (%) Example 21 I-28 (0.1) z38 (0.2) (27) 5 g DBN(0.02) W-1 A1/B1 — 0.35 13.4 (24) 5 g (95/5) Example 22 I-25 (0.2) z44(0.5) (28) 5 g DIA (0.01) W-1 A1/B1 — 0.40 14.2 (25) 5 g HAP (0.01)(80/20) Example 23 I-1 (0.2) z2 (0.1) (29) 10 g TPSA (0.02) W-2 A1/B1 —0.40 14.6 (90/10) Example 24 I-4 (0.2) z42 (0.5) (30) 10 g HEP (0.01)W-2 A3/B2 — 0.40 14.8 (80/20) Example 25 I-17 (0.4) z40 (0.2) (31) 10 gDIA (0.02) W-3 A2/B1 — 0.40 14.9 (90/10) Comparative z2 (0.3) — (1) 10 gDBN (0.02) W-1 A1/B1 — 0.20 7.3 Example 1 (60/40) Comparative PAG-A(0.3) — (1) 10 g DBN (0.02) W-1 A1/B1 — No image No image Example 2(60/40) was formed. was formed.

From the results shown in Tables 3 to 5, it is clear that in the ArFexposure, the photosensitive compositions of the invention are excellentsuch that they are little in the density dependency and wide in theexposure latitude.

Examples 26 to 28 and Comparative Examples 3 and 4

(1) Formation of Lower Resist Layer:

An FHi-028DD resist (resist for i-rays, manufactured by Fujifilm OlinCo., Ltd.) was coated on a 6 inch silicon wafer using a spin coater Mark8, manufactured by Tokyo Electron Limited and baked at 90° C. for 90seconds to obtain a uniform film having a thickness of 0.55 μm.

This film was further heated at 200° C. for 3 minutes to form a lowerresist layer having a thickness of 0.40 μm.

(2) Formation of Upper Resist Layer:

Components shown in the following Table 6 were dissolved in a solvent toprepare solutions each having a concentration of solids of 11% byweight. The solution was subjected to microfiltration with a membranefilter having an opening of 0.1 μm, to prepare an upper resistcomposition.

The upper resist composition was coated on the lower resist layer in thesame way and heated at 130° C. for 90 seconds to form an upper resistlayer having a thickness of 0.20 μm.

Resins (SI-1) to (SI-3) in Table 6 are as follows.

Molecular weight (SI-1)

15000 (SI-2)

14500 (SI-3)

9600(3) Evaluation of Resist:

The resulting wafer was exposed by installing a resolution mask in anArF excimer stepper 9300, manufactured by ISI and changing the exposureamount.

Next, after heating at 120° C. for 90 seconds, the exposed wafer wasdeveloped with a tetrahydroammonium hydroxide developer (2.38% byweight) for 60 seconds, rinsed with distilled water, and then dried toobtain an upper pattern.

The density dependency and exposure latitude were evaluated in the samemanner as in Examples 1 to 25. The results are shown in Table 6.

TABLE 6 Formulation Associative Evaluation Acid acid Basic SolventDensity Exposure generating generating Resin compound Surfactant (weightComponent dependency latitude agent (g) agent (g) (10 g) (g) (0.03 g)ratio) (C) (g) (μm) (%) Example 26 I-1 (0.3) — SI-1 DIA (0.02) W-4 A1/B1— 0.350 10.1 PEA (0.02) (60/40) Example 27 I-2 (0.5) — SI-2 DIA (0.02)W-4 A1/B1 — 0.300 11.4 PEA (0.02) (60/40) Example 28 I-3 (0.4) — SI-3DIA (0.02) W-4 A1/B1 — 0.325 10.8 PEA (0.02) (60/40) Comparative z2(0.3) — SI-1 DIA (0.02) W-4 A1/B1 — 0.20 7.3 Example 3 PEA (0.02)(60/40) Comparative PAG-A (0.3) — SI-1 DIA (0.02) W-4 A1/B1 — No imageNo image Example 4 PEA (0.02) (60/40) was formed. was formed.

From the results shown in Table 6, it is clear that in the case of usinga double-layer resist, the photosensitive compositions of the inventionare excellent such that they are little in the density dependency andwide in the exposure latitude.

Examples 29 to 48 and Comparative Examples 5 and 6

<Preparation of Resist>

Components shown in the following Tables 7 to 8 were dissolved in asolvent to prepare solutions each having a concentration of solids of 5%by weight. The solution was filtered by a 0.1 μm polyethylene filter toprepare a resist solution.

The resist solution was coated on a hexamethyl disilazane-treated waferusing a spin coater and dried by heating on a vacuum contact type hotplate at 120° C. for 90 seconds to obtain a resist film having athickness of 0.1 μm.

The resulting resist film was subjected to pattern exposure using an F₂excimer laser stepper (157 nm), and immediately after the exposure,heated on a hot plate at 120° C. for 90 seconds. Further, the resultingresist film was developed with a 2.38% by weight tetramethylammoniumhydroxide aqueous solution for 60 seconds and rinsed with pure water toobtain a sample wafer. The sample was evaluated with respect to thedensity dependency and exposure latitude.

(Density Dependency)

In a line-and-space pattern with a line width of 80 nm (dense pattern:line-and-space=1/1) and an isolated line pattern (coarse pattern:line-and-space=1/5), an overlapping range of the depth of focus allowing(80 nm±10%) therebetween was determined. The larger the value, thesmaller the performance difference between the dense pattern and thecoarse pattern is, i.e., the density dependency is good.

(Exposure Latitude)

The exposure amount of reproducing a mask pattern of line-and-space witha line width of 80 nm was defined as an optimum exposure amount. Whenthe exposure amount was changed, a width of the exposure amount allowing(80 nm±10%) of the pattern size was determined. This value was dividedby the optimum exposure amount and expressed in terms of percentage. Thelarger the value, the smaller the performance change by the change ofthe exposure amount is, i.e., the exposure latitude is good.

The results are shown in Tables 7 to 8.

TABLE 7 Formulation Associative Evaluation Acid acid Basic SolventDensity Exposure generating generating compound Surfactant (weightComponent dependency latitude agent (g) agent (g) Resin (g) (g) (0.03 g)ratio) (C) (g) (μm) (%) Example 29 I-1 (0.3) — FII-1 (10) DIA (0.05) W-1A1/B1 — 0.325 11.2 (60/40) Example 30 I-2 (0.5) — FII-2 (10) TPI (0.04)W-1 A1/B2 — 0.300 10.3 (80/40) Example 31 I-3 (0.4) — FII-8 (8) TOA(0.04) W-2 A1/B1 — 0.325 10.6 FII-33 (2) (125/5) Example 32 I-4 (0.2)z38 (0.15) FII-11 (4) HEP (0.06) W-2 A1/B1 — 0.350 11.6 z50 (0.2) FII-34(6) (100/40) Example 33 I-5 (0.5) z27 (0.2) FII-12 (3) DBN (0.05) W-3A1/B2 — 0.325 10.8 FII-35 (7) (110/40) Example 34 I-6 (0.4) z35 (0.2)FII-13 (10) DIA (0.04) W-1 A1/B1 — 0.375 10.2 PEA ((0.04) (80/70)Example 35 I-1 (0.4) — FII-14 (9) TPA (0.04) W-2 A1/B2 — 0.300 11.2FII-39 (1) (90/60) Example 36 I-10 (0.4) z18 (0.15) FII-16 (10) TPSA(0.1) W-4 A1/B2 — 0.325 11.8 z49 (0.2) (70/40) Example 37 I-7 (0.5) z34(0.1) FII-18 (5) TBAH (0.03) W-1 A1/B2 — 0.400 10.5 z52 (0.2) FII-1 (5)(80/30) Example 38 I-8 (0.4) z3 (0.2) FII-20 (5) TMEA (0.05) W-1 A1/B1 —0.365 11.4 FII-5 (5) (80/70)

TABLE 8 Formulation Associative Evaluation Acid acid Basic SolventDensity Exposure generating generating Resin compound Surfactant (weightComponent dependency latitude agent (g) agent (g) (g) (g) (0.03 g)ratio) (C) (g) (μm) (%) Example 39 I-11 (0.6) z18 (0.1) FII-27 (5) HAP(0.05) W-1 A1/B1 — 0.325 10.1 z32 (0.2) FII-32 (5) (60/40) Example 40I-13 (0.6) z38 (0.15) FII-28 (5) DBN (0.04) W-2 A2/B1 — 0.300 11.8FII-27 (5) (70/80) Example 41 I-12 (0.2) z14 (0.15) FII-29 (8) DIA(0.01) W-1 A1/B2 — 0.375 10.4 z51 (0.2) FII-3 (2) PEA (0.01) (100/60)Example 42 I-16 (0.5) z38 (0.2) FII-30 (2) PEA (0.05) W-1 A1/B1 — 0.32510.3 z54 (0.1) FII-31 (5) (110/70) Example 43 I-18 (0.2) z2 (0.1) FII-38(10) TPI (0.04) W-1 A1/B2 — 0.350 11.4 z31 (0.1) (80/40) Example 44 I-14(0.2) z6 (0.1) FII-40 (5) TOA (0.04) W-2 A1/B2 — 0.300 11.8 z22 (0.1)FII-1 (5) (125/5) Example 45 I-15 (0.6) — FII-19 (3) HEP (0.06) W-2A1/B1 — 0.375 10.2 FII-28 (7) (100/40) Example 46 I-17 (0.2) z44 (0.4)FII-11 (5) DBN (0.03) W-3 A1/B2 — 0.350 11.1 FII-3 (5) (110/40) Example47 I-20 (0.2) z38 (0.15) FII-32 (4) DIA (0.04) W-1 A1/B1 — 0.300 10.5z40 (0.2) FII-30 (6) PEA (0.04) (80/70) Example 48 I-23 (0.1) z40 (0.3)FII-5 (7) TPA (0.04) W-2 A1/B2 — 0.350 10.9 z42 (0.1) FII-28 (3) (90/60)Comparative z2 (0.3) — FII-1 (10) DIA (0.05) W-1 A1/B1 — 0.25 6.1Example 5 (60/40) Comparative PAG-A (0.3) — FII-1 (10) DIA (0.05) W-1A1/B1 — No image No image Example 6 (60/40) was formed. was formed.

From the results shown in Tables 7 to 8, it is clear that in the F₂excimer laser exposure, the photosensitive compositions of the inventionare excellent such that they are little in the density dependency andwide in the exposure latitude.

Examples 49 to 60 and Comparative Examples 7 and 8

<Preparation of Resist>

Components shown in the following Table 10 were dissolved in a solventand filtered by a 0.1 μm polytetrafluoroethylene filter to preparepositive working resist solutions each having a concentration of solidsof 14% by weight.

The prepared positive working resist solutions were evaluated accordingto the following methods. The results are shown in Table 10.

The following Table 9 shows a molar ratio and a weight average molecularweight of each of resins (R-2) to (R-24) in Table 10.

TABLE 9 Molar ratio of repeating units (corresponding in order fromWeight average Resin the left) molecular weight R-2 60/40 12000 R-760/30/10 18000 R-8 60/20/20 12000 R-9 10/50/40 13000 R-17 10/70/20 15000R-22 70/30 12000 R-23 10/60/30 8000 R-24 50/20/30 16000PHS: Polyhydroxystyrene VP-8000 (manufactured by Nippon Soda Co., Ltd.)

Structures of dissolution inhibiting compounds (C-1) and (C-2) in Table9 are as follows.

<Evaluation of Resist>

Each of the prepared positive working resist solutions was uniformlycoated on a hexamethyldisilazne-treated silicon substrate using a spincoater and dried by heating on a hot plate at 120° C. for 90 seconds toform a 0.6 μm-thick resist film.

This resist film was subjected to pattern exposure using a mask forline-and-space and using a KrF excimer laser stepper (NA=0.63), andimmediately after the exposure, dried on a hot plate at 110° C. for 90seconds. Further, the resulting resist film was developed with a 2.38%by weight tetramethylammonium hydroxide aqueous solution at 23° C. for60 seconds, rinsed with pure water for 30 seconds, and then dried toform a line pattern. The resulting resist film was evaluated withrespect to the density dependency and exposure latitude.

(Density Dependency)

In a line-and-space pattern with a line width of 0.13 μm (dense pattern:line-and-space=1/1) and an isolated line pattern (coarse pattern:line-and-space=1/5), an overlapping range of the depth of focus allowing(0.13 μm±10%) therebetween was determined. The larger the value, thesmaller the performance difference between the dense pattern and thecoarse pattern is, i.e., the density dependency is good.

(Exposure Latitude)

The exposure amount of reproducing a mask pattern of line-and-space witha line width of 0.13 μm was defined as an optimum exposure amount. Whenthe exposure amount was changed, a width of the exposure amount allowing(0.13 μm±10%) of the pattern size was determined. This value was dividedby the optimum exposure amount and expressed in terms of percentage. Thelarger the value, the smaller the performance change by the change ofthe exposure amount is, i.e., the exposure latitude is good.

TABLE 10 Formulation Associative Evaluation Acid acid Basic SolventDensity Exposure generating generating Resin compound Surfactant (weightComponent dependency latitude agent (g) agent (g) (10 g) (g) (0.03 g)ratio) (C) (g) (μm) (%) Example 49 I-1 (0.3) — R-2 DBN (0.02) W-1 A1/B1— 0.40 14.4 (60/40) Example 50 I-2 (0.5) — R-7 TPI (0.03) W-1 A1/B1 —0.50 13.9 (60/40) Example 51 I-3 (0.4) — R-8 TPSA (0.01) W-2 A1/B1 —0.40 13.3 (60/40) Example 52 I-4 (0.2) z4 (0.3) R-9 HEP (0.02) W-2 A3/B1— 0.55 14.6 (80/20) Example 53 I-5 (0.4) z12 (0.2) R-17 DIA (0.05) W-3A2/B1 — 0.45 13.2 (90/10) Example 54 I-6 (0.4) z14 (0.3) R-23 DCMA(0.03) W-4 A4/B1 — 0.60 12.6 (90/10) Example 55 I-1 (0.3) z17 (0.3) R-24TPA (0.01) W-4 A1/B1 — 0.40 13.5 (50/50) Example 56 I-10 (0.3) z31 (0.4)R-2/R-23 = TOA (0.005) W-4 A1/B1 — 0.50 14.8 z49 (0.2) 50/50 (90/10)Example 57 I-7 (0.5) z34 (0.3) R-17/R-2 = TBAH (0.0015) W-4 A5/B2 — 0.5514.1 z52 (0.2) 30/70 (90/10) Example 58 I-8 (0.4) z40 (0.2) R-2/R-22 =TMEA (0.02) W-4 A1/B1 — 0.60 13.2 50/50 (95/5) Example 59 I-11 (0.6) z1(0.2) PHS HAP (0.01) W-1 A1/B1 C-1 (2) 0.45 13.8 (90/10) Example 60 I-21(0.2) z5 (0.2) R-2 DBN (0.002) W-2 A1/B1 C-2 (1) 0.40 12.9 (95/5)Comparative z2 (0.3) — R-2 DBN (0.02) W-1 A1/B1 — 0.25 8.9 Example 7(60/40) Comparative PAG-A (0.3) — R-2 DBN (0.02) W-1 A1/B1 — 0.35 4.3Example 8 (60/40)

From the results shown in Table 10, it is noted that the photosensitivecompositions of the invention are excellent as a positive working resistcomposition in the KrF excimer laser exposure such that they are littlein the density dependency and wide in the exposure latitude.

Examples 61 to 72 and Comparative Examples 9 and 10

<Preparation of Resist>

Components shown in the following Table 11 were dissolved in a solventand filtered by a 0.1 μm polytetrafluoroethylene filter to preparenegative working resist solutions each having a concentration of solidsof 14% by weight.

The prepared negative working resist solutions were evaluated in thesame methods as in Examples 49 to 60. The results are shown in Table 11.

Structures, molecular weights, and molecular weight distributions ofalkali-soluble resins in Table 11 will be given below.

Mw Mw/Mn P-1

17000 2.15 P-2

16000 2.30 P-3

19000 2.2 P-4

12000 1.2 P-5

21000 2.1 P-6

6000 1.2 VP-5000, manufactured by Nippon Soda Co. Ltd.

Structures of crosslinking agents in Table 11 will be given below.

TABLE 11

Formulation Evaluation Associative Acid acid Basic Density generatinggenerating Resin compound Surfactant Solvent Component dependencyExposure agent (g) agent (g) (10 g) (g) (0.03 g) (weight ratio) (C) (g)(μm) latitude (%) Example 61 I-1 (0.3) — P-1 DIA (0.05) W-1 A1/B1 CL-1(2) 0.60 15.0 (60/40) Example 62 I-2 (0.5) — P-2 TPI (0.03) W-1 A1/B1CL-2 (3) 0.55 14.4 (60/40) Example 63 I-3 (0.4) — P-3 TOA (0.005) W-2A1/B1 CL-3 (2.5) 0.50 14.6 (60/40) Example 64 I-4 (0.2)  z4 (0.3) P-4HEP (0.02) W-2 A3/B1 CL-4 (3) 0.45 13.9 (80/20) Example 65 I-5 (0.4) z12(0.2) P-5 DBN (0.03) W-3 A2/B1 CL-5 (1.5) 0.55 14.9 (90/10) Example 66I-6 (0.4) z14 (0.3) P-6 DCMA (0.03) W-4 A4/B1 CL-6 (3) 0.55 13.3 (90/10)Example 67 I-1 (0.3) z17 (0.3) P-1 TPA (0.01) W-4 A1/B1 CL-7 (2.5) 0.6012.9 (50/50) Example 68 I-10 (0.3) z31 (0.4) P-2/P-6 TPSA (0.1) W-4A1/B1 CL-8 (2.5) 0.50 13.6 z49 (0.2) (80/20) (90/10) Example 69 I-7(0.5) z34 (0.3) P-3 TBAH W-4 A5/B2 CL-1 (2) 0.45 12.3 z52 (0.2) (0.015)(90/10) CL-5 (2) Example 70 I-8 (0.4) z40 (0.2) P-4 TMEA (0.02) W-4A1/B1 CL-2 (1) 0.45 14.7 (95/5)  CL-7 (2) Example 71 I-11 (0.6)  z1(0.2) P-5 HAP (0.01) W-1 A1/B1 CL-1 (2.5) 0.50 13.5 (90/10) Example 72I-21 (0.2)  z5 (0.2) P-6 DBN (0.002) W-2 A1/B1 CL-2 (2.5) 0.55 12.2(95/5)  Comparative z2 (0.3) — P-1 DIA (0.05) W-1 A1/B1 CL-1 (2) 0.209.1 Example 9 (60/40) Comparative PAG-A — P-1 DIA (0.05) W-1 A1/B1 CL-1(2) 0.30 3.6 Example 10 (0.3) (60/40)

From the results shown in Table 11, it is noted that the photosensitivecompositions of the invention are excellent as a negative working resistcomposition in the KrF excimer laser exposure such that they are littlein the density dependency and wide in the exposure latitude.

Examples 73 to 84 and Comparative Examples 11 and 12

<Preparation of Resist>

Components shown in the following Table 12 were dissolved in a solventand filtered by a 0.1 μm polytetrafluoroethylene filter to preparepositive working resist solutions each having a concentration of solidsof 12% by weight.

The prepared positive working resist solutions were evaluated accordingto the following methods. The results are shown in Table 12.

<Evaluation of Resist>

Each of the prepared positive working resist solutions was uniformlycoated on a hexamethyldisilazane-treated silicon substrate using a spincoater and dried by heating on a hot plate at 120° C. for 60 seconds toform a 0.3 μm-thick resist film.

This resist film was irradiated by an electron beam projectionlithography device, manufactured by Nikon Corporation (acceleratingvoltage: 100 keV), and immediately after the exposure, heated on a hotplate at 110° C. for 90 seconds. Further, the resulting resist film wasdeveloped with a 2.38% by weight tetramethylammonium hydroxide aqueoussolution at 23° C. for 60 seconds, rinsed with pure water for 30seconds, and then dried to form a contact hole pattern.

(Density Dependency)

A pattern size of an isolated contact hole (pitch: 1,000 nm) in a dosefor resolving a dense contact hole (pitch: 300 nm) of 100 nm wasmeasured, and a difference from 100 nm was calculated. The smaller thevalue, the smaller the performance difference between a dense patternand an isolated pattern is, i.e., the density dependency is good.

(Exposure Latitude)

A dose for resolving a dense contact hole (pitch: 300 nm) of 100 nm wasdefined as an optimum dose. When the dose was changed, a width of thedose allowing (100 nm±10%) of the pattern size was determined. Thisvalue was divided by the optimum dose and expressed in terms ofpercentage. The larger the value, the smaller the performance change bythe change of the exposure amount is, i.e., the exposure latitude isgood.

TABLE 12 Formulation Associative Evaluation Acid acid Basic SolventDensity Exposure generating generating Resin compound Surfactant (weightComponent dependency latitude agent (g) agent (g) (10 g) (g) (0.03 g)ratio) (C) (g) (μm) (%) Example 73 I-1 (0.3) — R-2 DBN (0.02) W-1 A1/B1— 5.2 12.4 (60/40) Example 74 I-2 (0.5) — R-7 TPI (0.03) W-1 A1/B1 — 5.512.1 (60/40) Example 75 I-3 (0.4) — R-8 TPSA (0.01) W-2 A1/B1 — 5.1 12.7(60/40) Example 76 I-4 (0.2) z4 (0.3) R-9 HEP (0.02) W-2 A3/B1 — 5.813.3 (80/20) Example 77 I-5 (0.4) z12 (0.2) R-17 DIA (0.05) W-3 A2/B1 —6.4 13.7 (90/10) Example 78 I-6 (0.4) z14 (0.3) R-23 DCMA (0.03) W-4A4/B1 — 5.6 12.4 (90/10) Example 79 I-1 (0.3) z17 (0.3) R-24 TPA (0.01)W-4 A1/B1 — 6.4 14.5 (50/50) Example 80 I-10 (0.3) z31 (0.4) R-2/R-23 =TOA (0.005) W-4 A1/B1 — 6.7 14.1 z49 (0.2) 50/50 (90/10) Example 81 I-7(0.5) z34 (0.3) R-17/R-2 = TBAH (0.0015) W-4 A5/B2 — 7.8 13.1 z52 (0.2)30/70 (90/10) Example 82 I-8 (0.4) z40 (0.2) R-2/R-22 = TMEA (0.02) W-4A1/B1 — 6.6 12.2 50/50 (95/5) Example 83 I-11 (0.6) z1 (0.2) PHS HAP(0.01) W-1 A1/B1 C-1 (2) 7.4 13.8 (90/10) Example 84 I-21 (0.2) z5 (0.2)R-2 DBN (0.002) W-2 A1/B1 C-2 (1) 5.8 13.9 (95/5) Comparative z2 (0.3) —R-2 DBN (0.02) W-1 A1/B1 — 12.5 7.4 Example 11 (60/40) Comparative PAG-A(0.3) — R-2 DBN (0.02) W-1 A1/B1 — 10.9 4.6 Example 12 (60/40)

From the results shown in Table 12, it is noted that the photosensitivecompositions of the invention are excellent as a positive working resistcomposition in the electron beam exposure such that they are little inthe density dependency and wide in the exposure latitude.

Examples 85 to 96 and Comparative Examples 13 and 14

<Preparation of Resist>

Components shown in the following Table 13 were dissolved in a solventand filtered by a 0.1 μm polytetrafluoroethylene filter to preparenegative working resist solutions each having a concentration of solidsof 12% by weight.

The prepared negative working resist solutions were evaluated accordingto the following methods. The results are shown in Table 13.

<Evaluation of Resist>

Each of the prepared negative working resist solutions was uniformlycoated on a hexamethyldisilazane-treated silicon substrate using a spincoater and dried by heating on a hot plate at 120° C. for 60 seconds toform a 0.3 μm-thick resist film.

This resist film was irradiated by an electron beam projectionlithography device, manufactured by Nikon Corporation (acceleratingvoltage: 100 keV), and immediately after the exposure, heated on a hotplate at 110° C. for 90 seconds. Further, the resulting resist film wasdeveloped with a 2.38% by weight tetramethylammonium hydroxide aqueoussolution at 23° C. for 60 seconds, rinsed with pure water for 30seconds, and then dried to form a line-and-space pattern.

(Density Dependency)

A pattern size of an isolated contact hole (pitch: 1,000 nm) in a dosefor resolving a dense line-and-space (pitch: 200 nm) of 100 nm wasmeasured, and a difference from 100 nm was calculated. The smaller thevalue, the smaller the performance difference between a dense patternand an isolated pattern is, i.e., the density dependency is good.

(Exposure Latitude)

A dose for resolving a dense line-and-space (pitch: 200 nm) of 100 nmwas defined as an optimum dose. When the dose was changed, a width ofthe dose allowing (100 nm±10%) of the pattern size was determined. Thisvalue was divided by the optimum dose and expressed in terms ofpercentage. The larger the value, the smaller the performance change bythe change of the exposure amount is, i.e., the exposure latitude isgood.

TABLE 13 Formulation Associative Evaluation Acid acid Basic SolventDensity Exposure generating generating Resin compound Surfactant (weightComponent dependency latitude agent (g) agent (g) (10 g) (g) (0.03 g)ratio) (C) (g) (μm) (%) Example 85 I-1 (0.3) — P-1 DIA (0.05) W-1 A1/B1CL-1 (2) 5.6 14.9 (60/40) Example 86 I-2 (0.5) — P-2 TPI (0.03) W-1A1/B1 CL-2 (3) 5.2 14.6 (60/40) Example 87 I-3 (0.4) — P-3 TOA (0.005)W-2 A1/B1 CL-3 (2.5) 5.9 14.1 (60/40) Example 88 I-4 (0.2) z4 (0.3) P-4HEP (0.02) W-2 A3/B1 CL-4 (3) 6.4 14.4 (80/20) Example 89 I-5 (0.4) z12(0.2) P-5 DBN (0.03) W-3 A2/B1 CL-5 (1.5) 6.8 13.9 (90/10) Example 90I-6 (0.4) z14 (0.3) P-6 DCMA (0.03) W-4 A4/B1 CL-6 (3) 5.4 13.8 (90/10)Example 91 I-1 (0.3) z17 (0.3) P-1 TPA (0.01) W-4 A1/B1 CL-7 (2.5) 7.112.5 (50/50) Example 92 I-10 (0.3) z31 (0.4) P-2/P-6 TPSA (0.1) W-4A1/B1 CL-8 (2.5) 5.8 14.6 z49 (0.2) (80/20) (90/10) Example 93 I-7 (0.5)z34 (0.3) P-3 TBAH (0.015) W-4 A5/B2 CL-1 (2) 6.3 12.9 z52 (0.2) (90/10)CL-5 (2) Example 94 I-8 (0.4) z40 (0.2) P-4 TMEA (0.02) W-4 A1/B1 CL-2(1) 7.7 13.7 (95/5) CL-7 (2) Example 95 I-11 (0.6) z1 (0.2) P-5 HAP(0.01) W-1 A1/B1 CL-1 (2.5) 5.6 14.5 (90/10) Example 96 I-21 (0.2) z5(0.2) P-6 DBN (0.002) W-2 A1/B1 CL-2 (2.5) 7.3 14.2 (95/5) Comparativez2 (0.3) — P-1 DIA (0.05) W-1 A1/B1 CL-1 (2) 13.1 8.4 Example 13 (60/40)Comparative PAG-A (0.3) — P-1 DIA (0.05) W-1 A1/B1 CL-1 (2) 11.6 3.9Example 14 (60/40)

From the results shown in Table 13, it is noted that the photosensitivecompositions of the invention are excellent as a negative working resistcomposition in the electron beam exposure such that they are little inthe density dependency and wide in the exposure latitude.

Examples 97 to 118 and Comparative Examples 15 to 17

<Preparation of Resist>

Components shown in the following Tables 14 to 16 were dissolved in asolvent to prepare solutions each having a concentration of solids of10% by weight. Each solution was filtered by a 0.1 μm polyethylenefilter to prepare a positive working resin solution. The preparedpositive resist solutions were evaluated according to the followingmethods. The results are shown in Tables 14 to 16. With respect to therespective components, in the case where the plural number of materialsare used, the given ratios are a weight ratio.

Symbols in Tables 14 to 16 are as follows.

-   N′-1: N,N-Dibutylaniline-   N′-2: N,N-Dipropylaniline-   N′-3: N,N-Dihydroxyethylaniline-   N′-4: 2,4,5-Triphenylimidazole-   N′-5: 2,6-Diisopropylaniline-   N′-6: Hydroxyantipyrine-   W′-1: Megaface F176 (manufactured by Dainippon Ink and Chemicals,    Incorporated) (fluorine based)-   W′-2: Megaface R₀₈ (manufactured by Dainippon Ink and Chemicals,    Incorporated) (fluorine and silicon based)-   W′-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu    Chemical Co., Ltd.)-   W′-4: Troysol S-366 (manufactured by Troy Chemical Industries, Inc.)-   SL′-1: Cyclopentanone-   SL′-2: Cyclohexanone-   SL′-3: 2-Methylcyclohexanone-   SL′-4: Propylene glycol monomethyl ether acetate-   SL′-5: Ethyl lactate-   SL′-6: Propylene glycol monomethyl ether-   SL′-7: 2-Heptanone-   SL′-8: γ-Butyrolactone-   SL′-9: Propylene carbonate-   SI′-1: t-Butyl lithocholate-   SI′-2: t-Butyl adamantanecarboxylate    <Evaluation of Resist>

ARC29A, manufactured by Brewer Science Limited was uniformly coated in athickness of 78 nm on a silicon wafer using a spin coater and dried byheating at 205° C. for 60 seconds to form an anti-refractive film.Thereafter, each of the positive working resist compositions immediatelyafter the preparation was coated using a spin coater and dried (PB) at atemperature shown in Tables 14 to 16 for 90 seconds to form a 300nm-thick resist film.

This resist film was exposed with an ArF excimer laser stepper (PAS5500/1100, manufactured by ASML, NA=0.75 (2/3 zonal illumination))through a mask, and immediately after the exposure, heated (PEB) on ahot plate at a temperature shown in Tables 14 to 16 for 90 seconds.Further, the resulting resist film was developed with a 2.38% by weighttetramethylammonium hydroxide aqueous solution at 23° C. for 60 seconds,rinsed with pure water for 30 seconds, and then dried to obtain a resistpattern.

[Density Dependency and Exposure Latitude]

The density dependency and exposure latitude were evaluated in the samemanner as in Example 1.

[Pattern Collapse]

With respect to a trench repeat pattern (pitch: 240 nm) with a linewidth of 110 nm, development and pattern formation were carried outwhile changing the exposure amount, and the presence or absence of thegeneration of pattern collapse due to an increase of the exposure amountwas observed by an scanning electron microscope (SEM). The line widthbecomes thin with an increase of the exposure amount, whereby patterncollapse is finally caused. According to the present evaluation method,a line width (CDmin) immediately before the generation of patterncollapse due to a reduction of the line width was defined as an index ofthe pattern collapse. That is, it is meant that when the CDmin is small,the pattern does not collapse even if the line width becomes thin, i.e.,the resist film is good such that the pattern collapse is hardly caused.

[Defocus Latitude (DOF) at the Time of Formation of Isolated LinePattern]

In an exposure amount of reproducing an isolated pattern of 210 nm intoa line width of 130 nm, the focus position was changed, and a width (nm)of the change of the focus satisfying the range of a line width of [130nm±13 nm (±10%)] was determined.

TABLE 14 Formulation Acid Disso- generating lution Evaluation agent ofOther acid inhi- Density Iso- the generating biting Basic Sur- Conditiondepen- Exposure lated Resin invention agent compound compound factantPB/PEB dency latitude Pattern DOF Example (2 g) (mg) (mg) Solvent (g) (4mg) (5 mg) (° C.) (nm) (%) collapse (nm) 97 RA1 I-1 (20) z1 (20)SL′-2/SL′-4 = — N′-1 W′-1 130/130 0.35 14.3 75 350 50/50 98 RA2 I-2 (18)z3 (20) SL′-2/SL′-6 = — N′-2 W′-2 130/130 0.40 14.8 72 375 70/30 99 RA3I-3 (23) z2 (20) SL′-1/SL′-4/ — N′-3 W′-3 120/120 0.40 14.5 72 375 SL′-8= 40/58/2 100 RA4 I-1 (15) z38 (20) SL′-2/SL′-4 = — N′-1 W′-4 115/1150.40 13.9 70 400 40/60 101 RA5 I-4 (15) z2 (20) SL′-2/SL′-4 = — N′-2W′-4 130/130 0.40 14.1 70 375 40/60 102 RA6 I-7 (22) z15 (20)SL′-2/SL′-4/ — N′-1/N′-3 = W′-4 130/130 0.45 15.6 68 400 SL′-9 = 1/140/59/1 103 RA7 I-1 (50) — SL′-2/SL′-4 = — N′-1 W′-1 115/120 0.45 15.870 425 50/50 104 RA8 I-17 (19) z16 (20) SL′-2/SL′-6 = — N′-3/N′-6 = W′-1115/115 0.40 14.2 72 375 70/30 1/1 105 RA9 I-1 (30) z44 (15)SL′-2/SL′-4/ — N′-2 W′-1 115/115 0.40 14.8 72 375 SL′-9 = 40/59/1 106RA10 I-18 (30) z14 (25) SL′-2/SL′-4 = — N′-3 W′-2 130/130 0.40 14.6 72375 40/60 107 RA11 I-1 (25) z36 (12) SL′-3/SL′-4 = — N′-1 W′-3 120/1200.45 15.3 70 376 40/60 108 RA12 I-5 (30) z40 (10) SL′-2/SL′-4 = — N′-1W′-4 130/130 0.40 14.7 75 350 40/60

TABLE 15 Formulation Acid generating Other acid Dissolution agent of thegenerating inhibiting Example Resin (2 g) invention (mg) agent (mg)Solvent compound (g) 109 RA13 I-12 (20) z38 (30) SL′-1/SL′-7 = SI′-1(0.1) 40/60 110 RA14 I-2 (18) z13 (27) SL′-2/SL′-4/SL′-9 = — 40/58/2 111RA15 I-3 (12) z14 (33) SL′-3/SL′-7 = — 60/40 112 RA16 I-2 (40) z27 (3)SL′-2/SL′-5 = — 60/40 113 RA17 I-2 (50) — SL′-2/SL′-7 = SI′-2 (0.1)60/40 114 RA18 I-1 (18) z13 (27) SL′-2/SL′-7 = — 60/40 115 RA19 I-3 (18)z13 (29) SL′-2/SL′-7 = — 60/40 116 RA20 I-2 (18) z13 (25) SL′-2/SL′-4 =— 40/60 117 RA21 I-1 (18) z13 (29) SL′-2 — 118 RA1 I-1 (20) z1 (20)SL′-4 — Formulation Evaluation Basic Condition Density Exposure Isolatedcompound Surfactant PB/PEB dependency latitude Pattern DOF Example (4mg) (5 mg) (° C.) (nm) (%) collapse (nm) 109 N′-6 W′-4 135/135 0.35 14.275 300 110 N′-4 W′-4 130/130 0.35 13.9 77 275 111 N′-4/N′-5 = 1/1 W′-3120/120 0.35 13.6 80 300 112 N′-3 W′-2 130/130 0.35 13.5 80 300 113 N′-3W′-2 130/130 0.35 13.6 78 275 114 N′-4/N′-5 = 1/1 W′-1 130/130 0.35 13.868 275 115 N′-3 W′-1 120/120 0.35 13.7 69 275 116 N′-3 W′-4 130/130 0.3513.6 69 275 117 N′-6 W′-1 130/130 0.35 13.9 78 300 118 N′-1 W′-1 130/1300.35 14.0 95 175

TABLE 16 Formulation Acid generating Other acid Dissolution ComparativeResin agent of the generating inhibiting Example (2 g) invention (mg)agent (mg) Solvent compound (g) 15 RA1 — z1 (24) SL′-2/SL′-4 = 50/50 —16 RA21 — z1 (24) SL′-2 — 17 RA21 — z1 (24) SL′-2 — FormulationEvaluation Basic Condition Density Exposure Isolated Comparativecompound Surfactant PB/PEB dependency latitude Pattern DOF Example (4mg) (5 mg) (° C.) (nm) (%) collapse (nm) 15 N′-1 W′-1 130/130 0.30 9.895 125 16 N′-1 W′-1 130/130 0.30 8.9 90 125 17 — — 130/130 0.30 10.0 9550

From the results shown in Tables 14 to 16, it is noted that the resistcompositions of the invention are excellent with respect to the densitydependency and exposure latitude.

Also, from the results shown in Tables 14 to 16, it is noted that byusing an alicyclic hydrocarbon based acid decomposable resin and acyclic ketone, the resist compositions of the invention are excellentsuch that they hardly cause pattern collapse and have a large defocuslatitude with respect to the isolated line pattern.

Examples 119 to 135 and Comparative Examples 18 to 19

<Preparation of Resist>

Components shown in the following Tables 17 to 18 were dissolved in asolvent to prepare solutions each having a concentration of solids of10% by weight and filtered by a 0.1 μm polyethylene filter to preparepositive working resist solutions. The prepared positive working resistsolutions were evaluated according to the following methods. The resultsare shown in Tables 17 to 18. With respect to the respective components,in the case where the plural number of materials are used, the givenratios are a weight ratio.

Symbols in Tables 17 to 18 are as follows.

[Photo Acid Generating Agent]

Corresponding to those enumerated previously.

[Basic Compound]

-   N″-1: N,N-Dibutylaniline-   N″-2: N,N-Dipropylaniline-   N″-3: N,N-Dihydroxyethylaniline-   N″-4: 2,4,5-Triphenylimidazole-   N″-5: 2,6-Diisopropylaniline-   N″-6: Hydroxyantipyrine    [Surfactant]-   W″-1: Megaface F176 (manufactured by Dainippon Ink and Chemicals,    Incorporated) (fluorine based)-   W″-2: Megaface R08 (manufactured by Dainippon Ink and Chemicals,    Incorporated) (fluorine and silicon based)-   W″-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu    Chemical Co., Ltd.) (silicon based)-   W″-4: Troysol S-366 (manufactured by Troy Chemical Industries, Inc.)    [Solvent]-   SL″-1: Propylene glycol monomethyl ether acetate-   SL″-2: Propylene glycol monomethyl ether propionate-   SL″-3: Propylene glycol monomethyl ether-   SL″-4: 3-Methoxybutanol-   SL″-5: Ethyl lactate-   SL″-6: Cyclohexanone-   SL″-7: 2-Heptanone-   SL″-8: γ-Butyrolactone-   SL″-9: Propylene carbonate    [Dissolution Inhibiting Compound]-   SI″-1: t-Butyl lithocholate-   SI″-2: t-Butyl adamantanecarboxylate    <Evaluation of Resist>

ARC29A, manufactured by Brewer Science Limited was uniformly coated in athickness of 78 nm on a silicon wafer using a spin coater and dried byheating at 205° C. for 60 seconds to form an anti-refractive film.Thereafter, each of the positive working resist compositions immediatelyafter the preparation was coated using a spin coater and dried (PB) at atemperature shown in Tables 17 to 18 for 60 seconds to form a 270nm-thick resist film.

This resist film was exposed with an ArF excimer laser stepper (PAS5500/1100, manufactured by ASML, NA=0.75 (2/3 zonal illumination))through a mask, and immediately after the exposure, heated (PEB) on ahot plate at a temperature shown in Tables 17 to 18 for 60 seconds.Further, the resulting resist film was developed with a 2.38% by weighttetramethylammonium hydroxide aqueous solution at 23° C. for 60 seconds,rinsed with pure water for 30 seconds, and then dried to obtain a resistpattern.

[Density Dependency and Exposure Latitude]

The density dependency and exposure latitude were evaluated in the samemanner as in Example 1.

[Evaluation Method of Process Window (Dense Pattern)]

With respect to a line-and-space pattern (pitch: 220 nm) with a masksize of 100 nm, when the exposure amount of reproducing in a size of 100nm was defined as an optimum exposure amount (E_(dense)), and themaximum exposure amount and the minimum exposure amount of reproducing aline width of the range of (100 nm±10%) under the condition ofdefocusing with ±0.3 μm against the best focus were defined as E₁ andE₂, respectively, the process window was defined as follows.|(E₁−E₂)/E_(dense)|×100(%)[Evaluation Method of Process Window (Isolated Pattern)]

With respect to an isolated pattern with a mask size of 160 nm, when theexposure amount of reproducing in a size of 100 nm was defined as anoptimum exposure amount (E_(iso)) and the maximum exposure amount andthe minimum exposure amount of reproducing a Line width of the range of(100 nm±10%) under the condition of defocusing with ±0.3 μm against thebest focus were defined as E₁₁ and E₁₂, respectively, the process windowwas defined as follows.|(E₁₁−E₁₂)/E_(iso)|×100(%)[Evaluation Method of Process Window (Common)]

With respect to an exposure amount range capable of simultaneouslyforming a dense pattern and an isolated pattern under the condition ofdefocusing with ±0.3 μm against the best focus, the common processwindow was calculated according to the following expression.|(E₂₁−E₂₂)/E_(dense)|×100(%)

Here, the exposure amount of smaller one between E₁ and E₁₁ is definedas E₂₁, and the exposure amount of larger one between E₂ and E₁₂ isdefined as E₂₂, respectively.

TABLE 17 Formulation Photo Dissolution acid generating Other photoinhibiting agent of the acid generating compound Example Resin (2 g)invention (mg) agent (mg) Solvent (g) 119 RB1 I-1 (45) — SL″-1/SL″-8 =95/5 — 120 RB2 I-10 (16) z15 (35) SL″-3/SL″-7 = 20/80 — 121 RB3 I-17(33) z14 (10) SL″-2/SL″-8 = 95/5 — 122 RB4 I-1 (15) z38 (30) SL″-1/SL″-3= 60/40 — 123 RB5 I-18 (30) z14 (25) SL″-1/SL″-3 = 70/30 — 124 RB6 I-17(12) z6 (30) SL″-1/SL″-6 = 60/40 — 125 RB7 I-1 (26) z2 (16)SL″-1/SL″-3/SL″-9 = 60/38/2 — 126 RB8 I-2 (30) z44 (20) SL″-1/SL″-5 =70/30 — 127 RB9 I-7 (18) z13 (25) SL″-1/SL″-6 = 60/40 — 128 RB10 I-4(14) z14 (15) SL″-1/SL″-5/SL″-8 = 70/29/1 SI″-1 (0.1) z50 (26) 129 RB11I-4 (25) z2 (18) SL″-1/SL″-3 = 60/40 — 130 RB12 I-8 (26) z1 (15)SL″-1/SL″-3 = 60/40 — Formulation Evaluation Basic Condition DensityExposure Process window (%) compound Surfactant PB/PEB dependencylatitude Dense Isolated Example (4 mg) (5 mg) (° C.) (nm) (%) patternpattern Common 119 N″-1 W″-1 130/130 0.40 14.8 8.0 7.0 6.0 120 N″-2 W″-4130/130 0.40 14.8 7.0 6.5 5.5 121 N″-5 W″-1 120/120 0.40 14.7 8.0 6.55.5 122 N″-3/N″-5 = 1/1 W″-4 115/115 0.40 14.5 9.0 8.0 7.0 123 N″-1 W″-1130/130 0.45 14.6 8.0 6.0 5.5 124 N″-1/N″-3 = 1/1 W″-4 130/130 0.45 15.38.5 8.0 7.0 125 N″-2/N″-3 = 1/1 W″-4 115/120 0.40 14.7 9.0 8.5 8.0 126N″-3 W″-2 120/120 0.40 14.4 8.0 7.5 6.5 127 N″-3 W″-3 120/120 0.40 14.98.0 7.5 7.0 128 N″-1 W″-2 130/130 0.35 13.9 8.0 6.5 5.5 129 N″-2/N″-3 =1/1 W″-3 115/115 0.35 13.7 8.0 7.5 7.0 130 N″-4 W″-1 115/115 0.35 13.68.0 7.0 5.5

TABLE 18 Formulation Photo acid generating Other Dissolution agent ofphoto acid inhibiting Basic Resin the inven- generating compoundcompound Surfactant (2 g) tion (mg) agent (mg) Solvent (g) (4 mg) (5 mg)Example 131 RB13 I-22 (30) z14 (25)  SL″-1/SL″-6 = — N″-2/N″-3 = W″-160/40 1/1 132 RB14  I-3 (30) Z1 (15) SL″-1/SL″-6 = SI″-2 N″-1 W″-1 60/40(0.1) 133 R1  I-1 (45) — SL″-1/SL″-8 = — N″-1 W″-1 95/5 134 R2  I-1 (45)— SL″-1/SL″-8 = — N″-1 W″-1 95/5 135 R3  I-1 (45) — SL″-1/SL″-8 = — N″-1W″-1 95/5 Comparative Example 18 RB1 — z1 (40) SL″-1/SL″-8 = — N″-1 W″-195/5 19 RB8 — z2 (40) SL″-1/SL″-6 = — N″-3 W″-2 70/30 EvaluationCondition Density Exposure Process window (%) PB/PEB dependency latitudeDense Isolated (° C.) (nm) (%) pattern pattern Common Example 131130/130 0.35 13.8 8.5 7.5 7.0 132 115/115 0.35 13.7 8.5 7.0 6.5 133130/130 0.35 13.8 3.5 3.0 2.0 134 130/130 0.35 13.3 3.0 2.0 1.0 135130/130 0.35 13.5 3.5 2.5 1.5 Comparative Example 18 130/130 0.30 9.77.0 3.0 1.0 19 120/120 0.30 8.6 6.0 3.0 2.0

From the results shown in Tables 17 to 18, it is noted that the resistcompositions of the invention are excellent with respect to the densitydependency and exposure latitude.

Also, from the results shown in Tables 17 to 18, it is noted that byusing an alicyclic hydrocarbon based acid decomposable resin (Baa), thepositive working resist compositions of the invention can ensure a wideprocess window in the formation of an isolated line and a dense pattern.

According to the invention, it is possible to provide an excellentphotosensitive composition and a pattern forming method using the same.

According to the invention, it is possible to provide an excellentphotosensitive composition having a wide exposure margin and littledensity dependency and a pattern forming method using the same.

According to the invention, it is possible to provide a positive workingresist composition that is low in the generation of pattern collapse inthe formation of a fine pattern of not more than 110 nm and wide in thedefocus latitude (DOF) in the formation of an isolated line pattern anda pattern forming method using the same.

According to the invention, it is possible to provide a positive workingresist composition capable of ensuring a wide process window in theformation of isolated line and dense patterns and a pattern formingmethod using the same.

The entire disclosure of each and every foreign patent application fromwhich the benefit of foreign priority has been claimed in the presentapplication is incorporated herein by reference, as if fully set forth.

1. A photosensitive composition comprising (A) a compound that generatesa sulfonic acid by irradiation with one of an actinic ray and aradiation, wherein the sulfonic acid is represented by general formula(I):A₁

A₂—SO₃H)_(n)  (I) in which A₁ represents a connecting group having avalence of n; each of A₂'s represents a single bond or a divalentaliphatic group, and A₂'s are the same or different, with proviso thatat least one of a group represented by A₁ and groups represented by A₂'shas a fluorine atom; and n represents an integer of from 2 to
 4. 2. Apositive photosensitive composition which is a photosensitivecomposition according to claim 1, further comprising (B) a resin thatincreases an solubility of the resin (B) in an alkaline developer by anaction of an acid.
 3. The positive photosensitive composition of claim2, wherein the resin (B) has a fluorine atom.
 4. The positivephotosensitive composition of claim 3, wherein the resin (B) has ahexafluoroisopropanol structure.
 5. The positive photosensitivecomposition of claim 2, wherein the resin (B) has a hydroxystyrenestructural unit.
 6. The positive photosensitive composition of claim 2,wherein the resin (B) is (Ba) a resin having a monocyclic or polycyclicalicyclic hydrocarbon structure.
 7. The positive photosensitivecomposition of claim 6, wherein the resin (B) further has a repeatingunit having a lactone structure.
 8. The positive photosensitivecomposition of claim 6, which further comprises: (Ha) a solventcomprising at least one cyclic ketone.
 9. The positive photosensitivecomposition of claim 2, wherein the resin (B) has at least one repeatingunit selected from a repeating unit represented by general formula (1),a repeating unit represented by general formula (2), and a repeatingunit represented by general formula (3), wherein the resin (Baa)increases a solubility of the resin (Baa) in an alkaline developer by anaction of an acid:

in which R represents a hydrogen atom or a methyl group; A represents asingle bond or a connecting group; and ALG represents a grouprepresented by any one of general formulae (pI) to (pV):

in which R₁₁ represents a methyl group, an ethyl group, an n-propylgroup, an isopropyl group, an n-butyl group, an isobutyl group, or asec-butyl group; Z represents an atomic group necessary for forming analicyclic hydrocarbon group together with a carbon atom; R₁₂ to R₁₆ eachindependently represents a linear or branched alkyl group having from 1to 4 carbon atoms or an alicyclic hydrocarbon group, with proviso thatat least one of R₁₂ to R₁₄ and any one of R₁₅ and R₁₆ represents analicyclic hydrocarbon group; R₁₇ to R₂₁ each independently represents ahydrogen atom, a linear or branched alkyl group having from 1 to 4carbon atoms or an alicyclic hydrocarbon group, with proviso that atleast one of R₁₇ to R₂₁ represents an alicyclic hydrocarbon group andany one of R₁₉ and R₂₁ represents a linear or branched alkyl grouphaving from 1 to 4 carbon atoms or an alicyclic hydrocarbon group; andR₂₂ to R₂₅ each independently represents a hydrogen atom, a linear orbranched alkyl group having from 1 to 4 carbon atoms or an alicyclichydrocarbon group, with proviso that at least one of R₂₂ to R₂₅represents an alicyclic hydrocarbon group and R₂₃ and R₂₄ may be takentogether to form a ring,

in which R_(1a) represents a hydrogen atom or a methyl group; W₁represents a single bond, or a single group or a combination of two ormore groups selected from the group consisting of an alkylene group, anether group, a thioether group, a carbonyl group, and an ester group;and Lc represents a lactone residue represented by any one of generalformulae (IV), (V-1) to (V-6) and (VI):

in which R_(a1), R_(b1), R_(c1), R_(d1), and R_(e1) each independentlyrepresents a hydrogen atom or an alkyl group having from 1 to 4 carbonatoms; and m and n each independently represents an integer of from 0 to3, and (m+n) is from 2 to 6,

in which R_(1b) to R_(5b) each independently represents a hydrogen atom,an alkyl group, a cycloalkyl group, an alkenyl group, or COOR_(6b),wherein R_(6b) represents an alkyl group, and two of R_(1b) to R_(5b)may be taken together to form a ring, and

in which R₃₀ represents a hydrogen atom or a methyl group; and R₃₁ toR₃₃ each independently represents a hydrogen atom, a hydroxyl group oran alkyl group, with proviso that at least one of R₃₁ to R₃₃ representsa hydroxyl group.
 10. The positive photosensitive composition of claim9, wherein the resin (B) has a repeating unit represented by the generalformula (1) and at least one repeating unit selected from a repeatingunit represented by the general formula (2) and a repeating unitrepresented by the general formula (3).
 11. The positive photosensitivecomposition of claim 9, wherein the resin (B) has a repeating unitrepresented by the general formula (1), a repeating unit represented bythe general formula (2), and a repeating unit represented by the generalformula (3).
 12. The positive photosensitive composition of claim 2,which further comprises (C) a dissolution inhibiting compound thatdecomposes by an action of an acid and increases a solubility of thecompound (C) in an alkaline developer, the compound (C) having amolecular weight of not more than 3,000.
 13. A positive photosensitivecomposition which is a photosensitive composition according to claim 1,further comprising: (D) a resin soluble in an alkaline developer; and(C) a dissolution inhibiting compound that decomposes by an action of anacid and increases a solubility of the compound (C) in an alkalinedeveloper, the compound (C) having a molecular weight of not more than3,000.
 14. A negative photosensitive composition which is aphotosensitive composition according to claim 1, further comprising: (D)a resin soluble in an alkaline developer; and (E) an acid crosslinkingagent that cross-links with the resin (D) by an action of an acid. 15.The photosensitive composition of claim 1, wherein in the generalformula (I), A₂ represents an aliphatic group having a structurerepresented by general formula (II):

in which Rf₁ and Rf₂ each independently represents a hydrogen atom, ahalogen atom, an alkyl group or a cycloalkyl group, with proviso that atleast one of Rf₁ and Rf₂ represents a fluorine atom or a fluoroalkylgroup.
 16. The photosensitive composition of claim 1, wherein thecompound (A) is one kind selected from a sulfonium salt compound of thesulfonic acid represented by the general formula (I), an iodonium saltcompound of the sulfonic acid represented by the general formula (I),and an ester compound of the sulfonic acid represented by the generalformula (I).
 17. The photosensitive composition of claim 1, wherein eachof —SO₃H's in the sulfonic acid represented by the general formula (I)directly connects a carbon atom to which at least one of a fluorine atomand a fluoroalkyl group is directly connected.
 18. The photosensitivecomposition of claim 1, which further comprises (A′) a compound havingone sulfonic acid group, the compound (A′) generating a sulfonic acid byirradiation with one of an actinic ray and a radiation.
 19. Thephotosensitive composition of claim 18, wherein the compound (A′) is amonovalent perfluoroalkanesulfonic acid sulfonium salt.
 20. Thephotosensitive composition of claim 1, which further comprises a mixedsolvent of a solvent containing a hydroxyl group in its structure and asolvent not containing a hydroxyl group in its structure.
 21. Thephotosensitive composition of claim 1, which further comprises at leastone of (F) a basic compound and (G) at least one of a surfactantcontaining a fluorine atom, a surfactant containing a silicon atom and asurfactant containing a fluorine atom and a silicon atom.
 22. Thephotosensitive composition of claim 21, wherein the basic compound (F)is at least one of (i) a compound having a structure selected from animidazole structure, a diazabicyclo structure, an onium hydroxidestructure, an onium carboxylate structure, a trialkylamine structure, ananiline structure, and a pyridine structure, (ii) an alkylaminederivative having at least one of a hydroxyl group and an ether bond and(iii) an aniline derivative having at least one of a hydroxyl group andan ether bond.
 23. A pattern forming method comprising: forming a filmby using a photosensitive composition of claim 1; exposing the film, soas to form a exposed film; and developing the exposed film.